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<body>
<div class="head">
<p>
<a href="http://www.w3.org/">
<img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" />
</a>
</p>
<h1 class="title" id="title">
JSON-LD
Syntax
1.0
</h1>
<h2 id="subtitle">
A
Context-based
JSON
Serialization
for
Linking
Data
</h2>
<del class="diff-old">Unofficial
Draft
22
May
</del>
<h2 id="final-community-group-specification-26-june-2012">
<ins class="diff-chg">Final
Community
Group
Specification
26
June
</ins>
2012
</h2>
<dl>
<dt>
<ins class="diff-new">Latest
editor's
draft:
</ins></dt><dd><a href="http://json-ld.org/spec/latest/json-ld-syntax/"><ins class="diff-new">
http://json-ld.org/spec/latest/json-ld-syntax/
</ins></a>
</dd>
<dt>
Editors:
</dt>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://manu.sporny.org/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="bibo:editor" inlist="">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
<dt>
Authors:
</dt>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://digitalbazaar.com/">
Manu
Sporny
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">
Dave
Longley
</a>,
<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
Digital
Bazaar
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
Gregg
Kellogg
</a>,
<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
Kellogg
Associates
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
Markus
Lanthaler
</a>,
<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
Graz
University
of
Technology
</a>
</span>
</dd>
<dd rel="dcterms:contributor">
<span typeof="foaf:Person">
<a rel="foaf:homepage" property="foaf:name" content="Mark Birbeck" href="http://webbackplane.com/">
Mark
Birbeck
</a>,
<a rel="foaf:workplaceHomepage" href="http://webbackplane.com/">
Backplane
Ltd.
</a>
</span>
</dd>
</dl>
<p>
This
document
is
also
available
in
this
non-normative
format:
<a href="diff-20120522.html">
diff
to
previous
version
<del class="diff-old">.
</del>
</a>
</p>
<p class="copyright">
<del class="diff-old">This
document
is
licensed
</del>
<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">
<ins class="diff-chg">Copyright
</ins></a><ins class="diff-chg">
©
2010-2012
the
Contributors
to
the
JSON-LD
Syntax
1.0
Specification,
published
by
the
</ins><a href="http://www.w3.org/community/json-ld/"><ins class="diff-chg">
JSON
for
Linking
Data
Community
Group
</ins></a>
under
<del class="diff-old">a
Creative
Commons
Attribution
3.0
License
</del>
<ins class="diff-chg">the
</ins><a href="https://www.w3.org/community/about/agreements/fsa/"><ins class="diff-chg">
W3C
Community
Final
Specification
Agreement
(FSA)
</ins>
</a>.
<ins class="diff-new">A
human-readable
</ins><a href="http://www.w3.org/community/about/agreements/fsa-deed/"><ins class="diff-new">
summary
</ins></a><ins class="diff-new">
is
available.
</ins>
</p>
<hr />
</div>
<div id="abstract" class="introductory section">
<h2>
Abstract
</h2>
<p>
JSON
has
proven
to
be
a
highly
useful
object
serialization
and
messaging
format.
In
an
attempt
to
harmonize
the
representation
of
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
in
JSON,
this
specification
outlines
a
common
JSON
representation
format
for
expressing
directed
graphs;
mixing
both
Linked
Data
and
non-Linked
Data
in
a
single
document.
</p>
</div>
<div id="sotd" class="introductory section">
<h2>
Status
of
This
Document
</h2>
<p>
This
<del class="diff-old">document
</del>
<ins class="diff-chg">specification
was
published
by
the
</ins><a href="http://www.w3.org/community/json-ld/"><ins class="diff-chg">
JSON
for
Linking
Data
Community
Group
</ins></a>.<ins class="diff-chg">
It
</ins>
is
<del class="diff-old">merely
</del>
<ins class="diff-chg">not
</ins>
a
<del class="diff-old">public
working
draft
</del>
<ins class="diff-chg">W3C
Standard
nor
is
it
on
the
W3C
Standards
Track.
Please
note
that
under
the
</ins><a href="https://www.w3.org/community/about/agreements/final/"><ins class="diff-chg">
W3C
Community
Final
Specification
Agreement
(FSA)
</ins></a><ins class="diff-chg">
other
conditions
apply.
Learn
more
about
</ins><a href="http://www.w3.org/community/"><ins class="diff-chg">
W3C
Community
and
Business
Groups
</ins></a>.</p><p><ins class="diff-chg">
This
document
has
been
under
development
for
over
18
months
in
the
JSON
for
Linking
Data
Community
Group.
The
document
has
recently
been
cleared
to
be
moved
into
the
RDF
Working
Group
for
review
and
publication
along
the
Recommendation
track.
This
specification
has
undergone
significant
development,
review,
and
changes
during
the
course
</ins>
of
<ins class="diff-new">the
last
18
months
and
is
being
published
as
</ins>
a
<del class="diff-old">potential
</del>
<ins class="diff-chg">Final
Community
Group
Specification
to
transition
the
work
into
the
RDF
Working
Group.
</ins></p><p><ins class="diff-chg">
There
are
currently
</ins><a href="http://json-ld.org/#impl"><ins class="diff-chg">
five
interoperable
implementations
</ins></a><ins class="diff-chg">
of
this
</ins>
specification.
<del class="diff-old">It
has
no
official
standing
</del>
<ins class="diff-chg">There
is
a
</ins><a href="https://github.com/json-ld/json-ld.org/tree/main/test-suite"><ins class="diff-chg">
fairly
complete
test
suite
</ins></a><ins class="diff-chg">
and
a
</ins><a href="http://json-ld.org/playground/"><ins class="diff-chg">
live
JSON-LD
editor
</ins></a><ins class="diff-chg">
that
is
capable
</ins>
of
<del class="diff-old">any
kind
</del>
<ins class="diff-chg">demonstrating
the
features
described
in
this
document.
While
development
on
implementations,
the
test
suite
</ins>
and
<del class="diff-old">does
not
represent
</del>
the
<del class="diff-old">support
or
consensus
of
any
standards
organisation.
</del>
<ins class="diff-chg">live
editor
will
continue,
they
are
believed
to
be
mature
enough
to
be
integrated
into
a
non-production
system
at
this
point
in
time
with
the
expectation
that
they
could
be
used
in
a
production
system
within
the
next
year.
</ins>
</p>
<p>
<del class="diff-old">This
document
is
an
experimental
work
</del>
<ins class="diff-chg">There
are
a
number
of
ways
that
one
may
participate
</ins>
in
<del class="diff-old">progress.
</del>
<ins class="diff-chg">the
development
of
this
specification:
</ins>
</p>
<ul>
<li>
<ins class="diff-new">If
you
want
to
make
sure
that
your
feedback
is
formally
addressed
by
the
RDF
Working
Group,
you
should
send
it
to
public-rdf-comments:
</ins><a href="http://lists.w3.org/Archives/Public/public-rdf-comments/"><ins class="diff-new">
public-rdf-comments@w3.org
</ins></a></li><li><ins class="diff-new">
Ad-hoc
technical
discussion
primarily
occurs
on
the
public
community
mailing
list:
</ins><a href="http://lists.w3.org/Archives/Public/public-linked-json/"><ins class="diff-new">
public-linked-json@w3.org
</ins></a></li><li><a href="http://json-ld.org/minutes/"><ins class="diff-new">
Public
JSON-LD
Community
Group
teleconferences
</ins></a><ins class="diff-new">
are
held
on
Tuesdays
at
1500UTC
every
week.
</ins></li><li><ins class="diff-new">
RDF
Working
Group
teleconferences
are
held
on
Wednesdays
at
1500UTC
every
week.
Participation
is
limited
to
RDF
Working
Group
members.
</ins></li><li><ins class="diff-new">
Specification
bugs
and
issues
should
be
reported
in
the
</ins><a href="https://github.com/json-ld/json-ld.org/issues"><ins class="diff-new">
issue
tracker
</ins></a><ins class="diff-new">
if
you
do
not
want
to
send
an
e-mail
to
the
public-rdf-comments
mailing
list.
</ins></li><li><a href="https://github.com/json-ld/json-ld.org/tree/main/spec"><ins class="diff-new">
Source
code
</ins></a><ins class="diff-new">
for
the
specification
can
be
found
on
Github.
</ins></li><li><ins class="diff-new">
The
</ins><a href="http://webchat.freenode.net/?channels=json-ld"><ins class="diff-new">
#json-ld
</ins></a><ins class="diff-new">
IRC
channel
is
available
for
real-time
discussion
on
irc.freenode.net.
</ins></li></ul>
</div>
<div id="toc" class="section">
<h2 class="introductory">
Table
of
Contents
</h2>
<ul class="toc">
<li class="tocline">
<a href="#introduction" class="tocxref">
<span class="secno">
1.
</span>
Introduction
</a>
<ul class="toc">
<li class="tocline">
<a href="#how-to-read-this-document" class="tocxref">
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</a>
</li>
<del class="diff-old">1.2
Syntax
Tokens
and
Keywords
1.3
Contributing
</del>
</ul>
</li>
<li class="tocline">
<a href="#design-goals-and-rationale" class="tocxref">
<span class="secno">
2.
</span>
Design
Goals
and
Rationale
</a>
</li>
<li class="tocline">
<a href="#basic-concepts" class="tocxref">
<span class="secno">
3.
</span>
Basic
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a href="#linking-data" class="tocxref">
<span class="secno">
3.1
</span>
Linking
Data
</a>
<ul class="toc">
<li class="tocline">
<a href="#syntax-tokens-and-keywords" class="tocxref">
<span class="secno">
3.1.1
</span>
<ins class="diff-new">Syntax
Tokens
and
Keywords
</ins></a></li><li class="tocline"><a href="#the-context" class="tocxref"><span class="secno"><ins class="diff-new">
3.1.2
</ins></span>
The
Context
</a>
</li>
<li class="tocline">
<a href="#from-json-to-json-ld" class="tocxref">
<span class="secno">
<del class="diff-old">3.1.2
</del>
<ins class="diff-chg">3.1.3
</ins>
</span>
From
JSON
to
JSON-LD
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#iris" class="tocxref">
<span class="secno">
3.2
</span>
IRIs
</a>
</li>
<li class="tocline">
<a href="#identifying-the-subject" class="tocxref">
<span class="secno">
3.3
</span>
Identifying
the
Subject
</a>
</li>
<li class="tocline">
<a href="#specifying-the-type" class="tocxref">
<span class="secno">
3.4
</span>
Specifying
the
Type
</a>
</li>
<li class="tocline">
<a href="#string-internationalization" class="tocxref">
<span class="secno">
3.5
</span>
String
Internationalization
</a>
</li>
<li class="tocline">
<a href="#json-ld-syntax" class="tocxref">
<span class="secno">
3.6
</span>
<del class="diff-old">Sets
and
Lists
</del>
<ins class="diff-chg">JSON-LD
Syntax
</ins>
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#advanced-concepts" class="tocxref">
<span class="secno">
4.
</span>
Advanced
Concepts
</a>
<ul class="toc">
<li class="tocline">
<a href="#compact-iris" class="tocxref">
<span class="secno">
4.1
</span>
<del class="diff-old">Typed
Values
</del>
<ins class="diff-chg">Compact
IRIs
</ins>
</a>
</li>
<li class="tocline">
<a href="#typed-values" class="tocxref">
<span class="secno">
4.2
</span>
<del class="diff-old">Compact
IRIs
</del>
<ins class="diff-chg">Typed
Values
</ins>
</a>
</li>
<li class="tocline">
<a href="#external-contexts" class="tocxref">
<span class="secno">
4.3
</span>
External
Contexts
</a>
</li>
<li class="tocline">
<a href="#referencing-contexts-from-json-documents" class="tocxref">
<span class="secno">
4.4
</span>
Referencing
Contexts
from
JSON
Documents
</a>
</li>
<li class="tocline">
<a href="#expanded-term-definition" class="tocxref">
<span class="secno">
4.5
</span>
Expanded
Term
Definition
</a>
</li>
<li class="tocline">
<a href="#type-coercion" class="tocxref">
<span class="secno">
4.6
</span>
Type
Coercion
</a>
</li>
<li class="tocline">
<a href="#iri-expansion-within-a-context" class="tocxref">
<span class="secno">
4.7
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</a>
</li>
<li class="tocline">
<a href="#sets-and-lists" class="tocxref">
<span class="secno">
4.8
</span>
<ins class="diff-new">Sets
and
Lists
</ins></a></li><li class="tocline"><a href="#embedding" class="tocxref"><span class="secno"><ins class="diff-new">
4.9
</ins></span>
Embedding
</a>
</li>
<li class="tocline">
<a href="#named-graphs" class="tocxref">
<span class="secno">
<del class="diff-old">4.9
</del>
<ins class="diff-chg">4.10
</ins>
</span>
Named
Graphs
</a>
</li>
<li class="tocline">
<a href="#identifying-unlabeled-nodes" class="tocxref">
<span class="secno">
<del class="diff-old">4.10
</del>
<ins class="diff-chg">4.11
</ins>
</span>
Identifying
Unlabeled
Nodes
</a>
</li>
<li class="tocline">
<a href="#aliasing-keywords" class="tocxref">
<span class="secno">
<del class="diff-old">4.11
</del>
<ins class="diff-chg">4.12
</ins>
</span>
Aliasing
Keywords
</a>
</li>
<li class="tocline">
<a href="#expanded-document-form" class="tocxref">
<span class="secno">
<del class="diff-old">4.12
</del>
<ins class="diff-chg">4.13
</ins>
</span>
Expanded
Document
Form
</a>
</li>
<li class="tocline">
<a href="#compact-document-form" class="tocxref">
<span class="secno">
<del class="diff-old">4.13
</del>
<ins class="diff-chg">4.14
</ins>
</span>
Compact
Document
Form
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#json-ld-authoring-guidelines" class="tocxref">
<span class="secno">
A.
</span>
JSON-LD
<del class="diff-old">Grammar
</del>
<ins class="diff-chg">Authoring
Guidelines
</ins>
</a>
</li>
<li class="tocline">
<a href="#relationship-to-other-rdf-formats" class="tocxref">
<span class="secno">
B.
</span>
<del class="diff-old">Markup
Examples
</del>
<ins class="diff-chg">Relationship
to
other
RDF
Formats
</ins>
</a>
<ul class="toc">
<li class="tocline">
<a href="#rdf" class="tocxref">
<span class="secno">
B.1
</span>
<ins class="diff-new">RDF
</ins></a></li><li class="tocline"><a href="#turtle" class="tocxref"><span class="secno"><ins class="diff-new">
B.2
</ins></span>
Turtle
</a>
<ul class="toc">
<li class="tocline">
<a href="#prefix-definitions" class="tocxref">
<span class="secno">
<del class="diff-old">B.1.1
</del>
<ins class="diff-chg">B.2.1
</ins>
</span>
Prefix
definitions
</a>
</li>
<li class="tocline">
<a href="#embedding-1" class="tocxref">
<span class="secno">
<del class="diff-old">B.1.2
</del>
<ins class="diff-chg">B.2.2
</ins>
</span>
Embedding
</a>
</li>
<li class="tocline">
<a href="#lists" class="tocxref">
<span class="secno">
<del class="diff-old">B.1.3
</del>
<ins class="diff-chg">B.2.3
</ins>
</span>
Lists
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#rdfa" class="tocxref">
<span class="secno">
<del class="diff-old">B.2
</del>
<ins class="diff-chg">B.3
</ins>
</span>
RDFa
</a>
</li>
<li class="tocline">
<a href="#microformats" class="tocxref">
<span class="secno">
<del class="diff-old">B.3
</del>
<ins class="diff-chg">B.4
</ins>
</span>
Microformats
</a>
</li>
<li class="tocline">
<a href="#microdata" class="tocxref">
<span class="secno">
<del class="diff-old">B.4
</del>
<ins class="diff-chg">B.5
</ins>
</span>
Microdata
</a>
</li>
</ul>
</li>
<li class="tocline">
<a href="#iana-considerations" class="tocxref">
<span class="secno">
C.
</span>
IANA
Considerations
</a>
</li>
<li class="tocline">
<a href="#acknowledgements" class="tocxref">
<span class="secno">
D.
</span>
Acknowledgements
</a>
</li>
<li class="tocline">
<a href="#references" class="tocxref">
<span class="secno">
E.
</span>
References
</a>
<ul class="toc">
<li class="tocline">
<a href="#normative-references" class="tocxref">
<span class="secno">
E.1
</span>
Normative
references
</a>
</li>
<li class="tocline">
<a href="#informative-references" class="tocxref">
<span class="secno">
E.2
</span>
Informative
references
</a>
</li>
</ul>
</li>
</ul>
</div>
<div class="informative section" id="introduction">
<h2>
<span class="secno">
1.
</span>
Introduction
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
JSON,
as
specified
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
RFC4627
</a>
</cite>
],
is
a
simple
language
for
representing
data
on
the
Web.
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
is
a
technique
for
creating
a
network
of
inter-connected
data
across
different
Web
documents
and
Web
sites.
A
<em>
<del class="diff-old">thing
</del>
<ins class="diff-chg">document
</ins>
</em>
in
this
data
network
is
typically
identified
using
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(Internationalized
Resource
<del class="diff-old">Identifier),
which
is
</del>
<ins class="diff-chg">Identifier).
A
software
program
can
</ins>
typically
<del class="diff-old">dereference-able,
and
thus
may
be
used
to
</del>
<ins class="diff-chg">follow
an
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr><ins class="diff-chg">
just
like
you
follow
a
URL
by
putting
it
into
your
browser's
location
bar.
By
following
IRIs,
a
software
program
can
</ins>
find
more
information
about
the
<em>
<ins class="diff-new">document
</ins></em><ins class="diff-new">
and
the
</ins><em>
thing
<del class="diff-old">.
</del>
</em>
<ins class="diff-chg">s
that
the
document
describes.
These
</ins><em><ins class="diff-chg">
things
</ins></em><ins class="diff-chg">
may
also
be
identified
using
</ins><a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
s.
</ins>
The
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
allows
a
software
program
to
start
at
one
<em>
<del class="diff-old">thing
</del>
<ins class="diff-chg">document
</ins>
</em>
and
follow
links
to
other
<em>
<ins class="diff-new">documents
</ins></em><ins class="diff-new">
or
</ins><em>
things
</em>
in
order
to
learn
more
about
all
of
the
<em>
<ins class="diff-new">documents
</ins></em><ins class="diff-new">
and
</ins><em>
things
</em>
described
on
the
Web.
</p>
<p>
JSON-LD
is
designed
as
a
lightweight
syntax
that
can
be
used
to
express
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>.
It
is
primarily
intended
to
be
a
way
to
use
Linked
Data
in
Javascript
and
other
Web-based
programming
environments.
It
is
also
useful
when
building
inter-operable
Web
services
and
when
storing
Linked
Data
in
JSON-based
document
storage
engines.
It
is
practical
and
designed
to
be
as
simple
as
possible,
utilizing
the
large
number
of
JSON
parsers
and
libraries
available
today.
</p>
<p>
The
syntax
does
not
necessarily
require
applications
to
change
their
JSON,
but
allows
one
to
easily
add
meaning
by
simply
adding
or
referencing
a
context.
The
syntax
is
designed
to
not
disturb
already
deployed
systems
running
on
JSON,
but
provide
a
smooth
upgrade
path
from
JSON
to
JSON-LD.
Finally,
the
format
is
intended
to
be
easy
to
parse,
efficient
to
generate,
and
only
requires
a
very
small
memory
footprint
in
order
to
operate.
</p>
<div id="how-to-read-this-document" class="section">
<h3>
<span class="secno">
1.1
</span>
How
to
Read
this
Document
</h3>
<p>
<em>
<ins class="diff-new">This
section
is
non-normative.
</ins></em></p>
<p>
This
document
is
a
detailed
specification
for
a
serialization
of
Linked
Data
in
JSON.
The
document
is
primarily
intended
for
the
following
audiences:
</p>
<ul>
<li>
Software
developers
that
want
to
encode
Linked
Data
in
a
way
that
is
cross-language
compatible
via
JSON.
</li>
<li>
Software
developers
that
want
to
understand
the
design
decisions
and
language
syntax
for
JSON-LD.
</li>
<li>
Software
developers
that
want
to
implement
processors
and
APIs
for
JSON-LD.
</li>
</ul>
<p>
This
specification
does
not
describe
the
programming
interfaces
for
the
JSON-LD
Syntax.
The
specification
that
describes
the
programming
interfaces
for
JSON-LD
documents
is
the
JSON-LD
Application
Programming
Interface
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
JSON-LD-API
</a>
</cite>
].
</p>
<p>
To
understand
the
basics
in
this
specification
you
must
first
be
familiar
with
JSON,
which
is
detailed
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
RFC4627
</a>
</cite>
].
</p>
<p>
JSON
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
RFC4627
</a>
</cite>
]
defines
several
terms
which
are
used
throughout
this
document:
</p>
<dl>
<dt>
<dfn title="json_object" id="dfn-json_object">
JSON
object
</dfn>
</dt>
<dd>
An
object
structure
is
represented
as
a
pair
of
curly
brackets
surrounding
zero
or
more
name-value
pairs.
A
name
is
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>.
A
single
colon
comes
after
each
name,
separating
the
name
from
the
value.
A
single
comma
separates
a
value
from
a
following
name.
The
names
within
an
object
<em class="rfc2119" title="should">
should
</em>
be
unique.
</dd>
<dt>
<dfn title="array" id="dfn-array">
array
</dfn>
</dt>
<dd>
In
JSON,
an
array
is
an
<em>
ordered
</em>
<del class="diff-old">collection
</del>
<ins class="diff-chg">sequence
</ins>
of
<ins class="diff-new">zero
or
more
</ins>
values.
An
array
is
represented
as
square
brackets
surrounding
zero
or
more
values
that
are
separated
by
commas.
While
JSON-LD
uses
the
same
array
representation
as
JSON,
the
collection
is
<em>
unordered
</em>
by
default.
While
order
is
preserved
in
regular
JSON
arrays,
it
is
not
in
regular
JSON-LD
arrays
unless
specific
markup
is
provided
(see
<a href="#sets-and-lists">
Sets
and
Lists
</a>
).
</dd>
<dt>
<dfn title="string" id="dfn-string">
string
</dfn>
</dt>
<dd>
A
string
is
a
sequence
of
zero
or
more
Unicode
<del class="diff-old">(UTF-8)
</del>
characters,
wrapped
in
double
quotes,
using
backslash
escapes
(if
necessary).
A
character
is
represented
as
a
single
character
string.
</dd>
<dt>
<dfn title="number" id="dfn-number">
number
</dfn>
</dt>
<dd>
A
number
is
<del class="diff-old">is
</del>
similar
to
that
used
in
most
programming
languages,
except
that
the
octal
and
hexadecimal
formats
are
not
used
and
that
leading
zeros
are
not
allowed.
</dd>
<dt>
<dfn title="true" id="dfn-true">
true
</dfn>
and
<dfn title="false" id="dfn-false">
false
</dfn>
</dt>
<dd>
Values
that
are
used
to
express
one
of
two
possible
boolean
states.
</dd>
<dt>
<dfn title="null" id="dfn-null">
null
</dfn>
</dt>
<dd>
<del class="diff-old">Unless
otherwise
specified,
a
JSON-LD
processor
must
act
as
if
a
key-value
pair
in
</del>
<ins class="diff-chg">The
null
value
is
used
to
make
</ins>
the
<del class="diff-old">body
of
a
</del>
JSON-LD
<del class="diff-old">document
was
never
declared
when
</del>
<ins class="diff-chg">processor
&quot;forget&quot;
any
previously
defined
JSON
key
that
is
associated
with
</ins>
the
<del class="diff-old">value
equals
</del>
null
<del class="diff-old">.
</del>
<ins class="diff-chg">value.
</ins>
If
<del class="diff-old">@value
,
@list
,
or
@set
is
set
to
null
in
expanded
form,
then
</del>
<ins class="diff-chg">a
previous
definition
doesn't
exist,
</ins>
the
entire
<del class="diff-old">JSON
object
</del>
<ins class="diff-chg">key-value
</ins>
is
ignored.
If
<del class="diff-old">@context
is
set
to
null
,
the
active
context
is
reset
and
when
used
within
</del>
a
<del class="diff-old">context
,
it
removes
any
</del>
<ins class="diff-chg">previous
</ins>
definition
<del class="diff-old">associated
with
</del>
<ins class="diff-chg">of
</ins>
the
<del class="diff-old">key,
unless
otherwise
specified.
</del>
<ins class="diff-chg">key
does
exist,
the
previous
definition
is
undefined.
</ins>
</dd>
<dt>
<dfn title="subject_definition" id="dfn-subject_definition">
subject
definition
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
represent
a
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
and
one
or
more
properties
of
that
subject.
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
is
a
subject
definition
if
it
does
not
contain
they
keys
<code>
@value
</code>,
<code>
@list
</code>
or
<code>
@set
</code>
and
it
has
one
or
more
keys
other
than
<code>
@id
</code>.
</dd>
<dt>
<dfn title="subject_reference" id="dfn-subject_reference">
subject
reference
</dfn>
</dt>
<dd>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
reference
a
subject
having
only
the
<code>
@id
</code>
key.
</dd>
</dl>
<p>
</p>
</div>
<del class="diff-old">1.2
Syntax
Tokens
and
Keywords
JSON-LD
specifies
a
number
of
syntax
tokens
and
keywords
that
are
a
core
part
of
the
language:
@context
Used
to
define
the
short-hand
names
that
are
used
throughout
a
JSON-LD
document.
These
short-hand
names
are
called
term
s
and
help
developers
to
express
specific
identifiers
in
a
compact
manner.
The
@context
keyword
is
described
in
detail
in
the
section
titled
The
Context
.
@graph
Used
to
explicitly
express
a
linked
data
graph
.
@id
Used
to
uniquely
identify
things
that
are
being
described
in
the
document.
This
keyword
is
described
in
the
section
titled
Identifying
the
Subject
.
@value
Used
to
specify
the
data
that
is
associated
with
a
particular
property
in
the
graph.
This
keyword
is
described
in
the
sections
titled
String
Internationalization
and
Typed
Values
.
@language
Used
to
specify
the
native
language
for
a
particular
value
or
the
default
language
of
a
JSON-LD
document.
This
keyword
is
described
in
the
section
titled
String
Internationalization
.
@type
Used
to
set
the
data
type
of
a
subject
or
typed
value
.
This
keyword
is
described
in
the
section
titled
Typed
Values
.
@container
Used
to
set
the
container
of
a
particular
value.
This
keyword
is
described
in
the
section
titled
Sets
and
Lists
.
@list
Used
to
express
an
ordered
set
of
data.
This
keyword
is
described
in
the
section
titled
Sets
and
Lists
.
@set
Used
to
express
an
unordered
set
of
data.
This
keyword
is
described
in
the
section
titled
Sets
and
Lists
.
:
The
separator
for
JSON
keys
and
values
that
use
compact
IRIs
.
For
the
avoidance
of
doubt,
all
keys,
keywords
,
and
values
in
JSON-LD
are
case-sensitive.
1.3
Contributing
There
are
a
number
of
ways
that
one
may
participate
in
the
development
of
this
specification:
Technical
discussion
typically
occurs
on
the
public
mailing
list:
public-linked-json@w3.org
Public
teleconferences
are
held
every
week
on
Tuesdays
at
1500
UTC.
Specification
bugs
and
issues
should
be
reported
using
the
issue
tracker
.
Source
code
for
the
specification
can
be
found
on
Github.
The
#json-ld
IRC
channel
is
available
for
real-time
discussion
on
irc.freenode.net.
</del>
</div>
<div class="informative section" id="design-goals-and-rationale">
<h2>
<span class="secno">
2.
</span>
Design
Goals
and
Rationale
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
A
number
of
design
goals
were
established
before
the
creation
of
this
markup
language:
</p>
<dl>
<dt>
Simplicity
</dt>
<dd>
No
extra
processors
or
software
libraries
should
be
necessary
to
use
JSON-LD
in
its
most
basic
form.
The
language
will
provide
developers
with
a
very
easy
learning
curve.
Developers
need
only
know
JSON
and
two
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keywords
</a>
(
<code>
@context
</code>
and
<code>
@id
</code>
)
to
use
the
basic
functionality
in
JSON-LD.
</dd>
<dt>
Compatibility
</dt>
<dd>
The
JSON-LD
markup
must
be
100%
compatible
with
JSON.
This
ensures
that
all
of
the
standard
JSON
libraries
work
seamlessly
with
JSON-LD
documents.
</dd>
<dt>
Expressiveness
</dt>
<dd>
The
syntax
must
be
able
to
express
directed
graphs,
which
have
been
proven
to
be
able
to
express
almost
every
real
world
data
model.
</dd>
<dt>
Terseness
</dt>
<dd>
The
JSON-LD
syntax
must
be
very
terse
and
human
readable,
requiring
as
little
effort
as
possible
from
the
developer.
</dd>
<dt>
Zero
Edits,
most
of
the
time
</dt>
<dd>
JSON-LD
must
provide
a
<a href="#referencing-contexts-from-json-documents">
mechanism
</a>
that
allows
developers
to
specify
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
in
a
way
that
is
out-of-band.
This
allows
organizations
that
have
already
deployed
large
JSON-based
infrastructure
to
add
meaning
to
their
JSON
documents
in
a
way
that
is
not
disruptive
to
their
day-to-day
operations
and
is
transparent
to
their
current
customers.
At
times,
mapping
JSON
to
a
graph
representation
can
become
difficult.
In
these
instances,
rather
than
having
JSON-LD
support
an
esoteric
use
case,
we
chose
not
to
support
the
use
case
and
support
a
simplified
syntax
instead.
So,
while
Zero
Edits
is
a
goal,
it
is
not
always
possible
without
adding
great
complexity
to
the
language.
</dd>
<dt>
One-pass
Processing
</dt>
<dd>
JSON-LD
supports
one-pass
processing,
which
results
in
a
very
small
memory
footprint
when
processing
documents.
For
example,
to
expand
a
JSON-LD
document
from
a
compacted
form,
only
one
pass
is
required
over
the
data.
</dd>
</dl>
</div>
<div class="normative section" id="basic-concepts">
<h2>
<span class="secno">
3.
</span>
Basic
Concepts
</h2>
<em>
<ins class="diff-new">This
section
is
normative.
</ins></em>
<p>
JSON-LD
is
designed
to
ensure
that
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
concepts
can
be
marked
up
in
a
way
that
is
simple
to
understand
and
create
by
Web
authors.
In
many
cases,
regular
JSON
markup
can
become
Linked
Data
with
the
simple
addition
of
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>.
As
more
JSON-LD
features
are
used,
more
semantics
are
added
to
the
JSON
markup.
</p>
<div id="linking-data" class="section">
<h3>
<span class="secno">
3.1
</span>
Linking
Data
</h3>
<p>
The
following
definition
for
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
is
the
one
that
will
be
used
for
this
specification.
</p>
<ol>
<li>
<dfn title="linked_data" id="dfn-linked_data">
Linked
Data
</dfn>
is
a
set
of
documents,
each
containing
a
representation
of
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
<del class="diff-old">graph.
</del>
<ins class="diff-chg">graph
</ins></a>.
</li>
<li>
A
<dfn title="linked_data_graph" id="dfn-linked_data_graph">
linked
data
graph
</dfn>
is
an
unordered
labeled
directed
graph,
where
nodes
are
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
s
or
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
s,
and
edges
are
<del class="diff-old">properties.
</del>
<ins class="diff-chg">labeled
using
</ins><a class="tref internalDFN" title="property" href="#dfn-property"><ins class="diff-chg">
properties
</ins></a>.
</li>
<li>
A
<dfn title="subject" id="dfn-subject">
subject
</dfn>
is
any
node
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
with
at
least
one
outgoing
edge.
</li>
<li>
A
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
<em class="rfc2119" title="should">
should
</em>
be
labeled
with
an
<dfn title="iri" id="dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
(an
Internationalized
Resource
Identifier
as
described
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC3987">
RFC3987
</a>
</cite>
]).
</li>
<li>
An
<dfn title="object" id="dfn-object">
object
</dfn>
is
a
node
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
with
at
least
one
incoming
edge.
</li>
<li>
An
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
<em class="rfc2119" title="may">
may
</em>
be
labeled
with
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<del class="diff-old">.
</del>
</a>
<ins class="diff-chg">or
a
label
that
is
not
an
</ins><a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
such
as
plain
text,
internationalized
text,
or
a
strictly-typed
data
value.
</ins>
</li>
<li>
A
node
<em class="rfc2119" title="may">
may
</em>
be
a
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
and
<ins class="diff-new">an
</ins>
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
at
the
same
time.
</li>
<li>
A
<dfn title="property" id="dfn-property">
property
</dfn>
is
<ins class="diff-new">the
label
on
</ins>
an
edge
<del class="diff-old">of
the
</del>
<ins class="diff-chg">in
a
</ins>
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>.
</li>
<li>
A
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>
<em class="rfc2119" title="should">
should
</em>
be
<del class="diff-old">labeled
with
</del>
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</li>
<li>
An
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
that
is
a
label
in
a
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
<em class="rfc2119" title="should">
should
</em>
be
dereferencable
to
a
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
document
describing
the
labeled
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>,
<del class="diff-old">object
or
</del>
<a class="tref internalDFN" title="property" href="#dfn-property">
property
<del class="diff-old">.
A
value
is
an
</del>
</a>
<ins class="diff-chg">or
</ins>
<a class="tref internalDFN" title="object" href="#dfn-object">
object
<del class="diff-old">with
a
label
that
is
not
an
</del>
</a>.
</li>
</ol>
<div class="issue">
<del class="diff-old">IRI
</del>
<div class="issue-title">
<span>
<ins class="diff-chg">Issue
1
</ins></span>
</div>
<p class="">
An
illustration
of
a
linked
data
graph
would
probably
help
here.
</p>
</div>
<div class="issue">
<div class="issue-title">
<span>
<ins class="diff-new">Issue
2
</ins></span></div><p class=""><ins class="diff-new">
EricP
suggests
that
the
definitions
of
subject
and
object,
while
being
practical,
are
at
odds
with
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS"><ins class="diff-new">
RDF-CONCEPTS
</ins></a></cite><ins class="diff-new">
]
use
in
their
roles
within
a
triple.
</ins></p></div><div class="note"><div class="note-title"><span><ins class="diff-new">
Note
</ins></span></div><p class=""><ins class="diff-new">
JSON-LD
allows
properties
to
be
BNodes,
while
RDF
does
not.
When
used
as
just
JSON-LD,
this
is
not
unreasonable;
it
only
becomes
an
issue
(and
could
raise
an
exception)
when
transformed
to
RDF.
</ins></p></div>
<p>
Note
that
the
definition
for
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
above
is
silent
on
the
topic
of
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
<del class="diff-old">nodes.
Unlabeled
</del>
nodes
<del class="diff-old">are
not
considered
Linked
Data
</del>
</a>.
<del class="diff-old">However,
</del>
<ins class="diff-chg">Nevertheless,
</ins>
this
specification
allows
for
the
expression
of
<del class="diff-old">unlabled
nodes,
</del>
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
<ins class="diff-chg">unlabeled
nodes
</ins></a>,
as
most
graph-based
data
sets
on
the
Web
contain
a
number
of
associated
nodes
that
are
not
named
and
thus
are
not
directly
de-referenceable.
</p>
<p>
JSON-LD
defines
a
mechanism
to
map
JSON
terms,
i.e.,
keys
and
values,
to
IRIs.
This
does
not
mean
that
JSON-LD
requires
every
key
or
value
to
be
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
but
rather
ensures
that
keys
and
values
can
be
mapped
to
IRIs
if
the
developer
desires
to
transform
their
data
into
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>.
There
are
a
few
techniques
that
can
ensure
that
developers
will
generate
good
Linked
Data
for
the
Web.
JSON-LD
formalizes
those
techniques.
</p>
<p>
We
will
be
using
the
following
JSON
markup
as
the
example
for
the
rest
of
this
section:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 1</span></div><pre class="example">{
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<div id="syntax-tokens-and-keywords" class="section">
<h4>
<span class="secno">
3.1.1
</span>
<ins class="diff-new">Syntax
Tokens
and
Keywords
</ins></h4><p><ins class="diff-new">
JSON-LD
specifies
a
number
of
syntax
tokens
and
</ins><dfn title="keyword" id="dfn-keyword"><ins class="diff-new">
keywords
</ins></dfn><ins class="diff-new">
that
are
a
core
part
of
the
language:
</ins></p><dl><dt><code><ins class="diff-new">
@context
</ins></code></dt><dd><ins class="diff-new">
Used
to
define
the
short-hand
names
that
are
used
throughout
a
JSON-LD
document.
These
short-hand
names
are
called
</ins><a class="tref internalDFN" title="term" href="#dfn-term"><ins class="diff-new">
term
</ins></a><ins class="diff-new">
s
and
help
developers
to
express
specific
identifiers
in
a
compact
manner.
The
</ins><code><ins class="diff-new">
@context
</ins></code><ins class="diff-new">
keyword
is
described
in
detail
in
the
section
titled
</ins><a href="#the-context"><ins class="diff-new">
The
Context
</ins></a>.</dd><dt><code><ins class="diff-new">
@graph
</ins></code></dt><dd><ins class="diff-new">
Used
to
explicitly
label
a
</ins><a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph"><ins class="diff-new">
linked
data
graph
</ins></a>.<ins class="diff-new">
This
keyword
is
described
in
the
section
titled
</ins><a href="#named-graphs"><ins class="diff-new">
Named
Graphs
</ins></a>.</dd><dt><code><ins class="diff-new">
@id
</ins></code></dt><dd><ins class="diff-new">
Used
to
uniquely
identify
</ins><em><ins class="diff-new">
things
</ins></em><ins class="diff-new">
that
are
being
described
in
the
document.
This
keyword
is
described
in
the
section
titled
</ins><a href="#identifying-the-subject"><ins class="diff-new">
Identifying
the
Subject
</ins></a>.</dd><dt><code><ins class="diff-new">
@value
</ins></code></dt><dd><ins class="diff-new">
Used
to
specify
the
data
that
is
associated
with
a
particular
</ins><a class="tref internalDFN" title="property" href="#dfn-property"><ins class="diff-new">
property
</ins></a><ins class="diff-new">
in
the
graph.
This
keyword
is
described
in
the
sections
titled
</ins><a href="#string-internationalization"><ins class="diff-new">
String
Internationalization
</ins></a><ins class="diff-new">
and
</ins><a href="#typed-values"><ins class="diff-new">
Typed
Values
</ins></a>.</dd><dt><code><ins class="diff-new">
@language
</ins></code></dt><dd><ins class="diff-new">
Used
to
specify
the
native
language
for
a
particular
value
or
the
default
language
of
a
JSON-LD
document.
This
keyword
is
described
in
the
section
titled
</ins><a href="#string-internationalization"><ins class="diff-new">
String
Internationalization
</ins></a>.</dd><dt><code><ins class="diff-new">
@type
</ins></code></dt><dd><ins class="diff-new">
Used
to
set
the
data
type
of
a
</ins><a class="tref internalDFN" title="subject" href="#dfn-subject"><ins class="diff-new">
subject
</ins></a><ins class="diff-new">
or
</ins><a class="tref internalDFN" title="typed_value" href="#dfn-typed_value"><ins class="diff-new">
typed
value
</ins></a>.<ins class="diff-new">
This
keyword
is
described
in
the
section
titled
</ins><a href="#typed-values"><ins class="diff-new">
Typed
Values
</ins></a>.</dd><dt><code><ins class="diff-new">
@container
</ins></code></dt><dd><ins class="diff-new">
Used
to
set
the
container
of
a
particular
value.
This
keyword
is
described
in
the
section
titled
</ins><a href="#sets-and-lists"><ins class="diff-new">
Sets
and
Lists
</ins></a>.</dd><dt><code><ins class="diff-new">
@list
</ins></code></dt><dd><ins class="diff-new">
Used
to
express
an
ordered
set
of
data.
This
keyword
is
described
in
the
section
titled
</ins><a href="#sets-and-lists"><ins class="diff-new">
Sets
and
Lists
</ins></a>.</dd><dt><code><ins class="diff-new">
@set
</ins></code></dt><dd><ins class="diff-new">
Used
to
express
an
unordered
set
of
data.
This
keyword
is
described
in
the
section
titled
</ins><a href="#sets-and-lists"><ins class="diff-new">
Sets
and
Lists
</ins></a>.</dd><dt><code>:</code></dt><dd><ins class="diff-new">
The
separator
for
JSON
keys
and
values
that
use
</ins><a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri"><ins class="diff-new">
compact
IRIs
</ins></a>.</dd></dl><p><ins class="diff-new">
For
the
avoidance
of
doubt,
all
keys,
</ins><a class="tref internalDFN" title="keyword" href="#dfn-keyword"><ins class="diff-new">
keywords
</ins></a>,<ins class="diff-new">
and
values
in
JSON-LD
are
case-sensitive.
</ins></p></div><div id="the-context" class="section"><h4><span class="secno"><ins class="diff-new">
3.1.2
</ins></span>
The
Context
</h4>
<p>
In
JSON-LD,
a
<dfn title="context" id="dfn-context">
context
</dfn>
is
used
to
map
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s,
i.e.,
properties
with
associated
values
in
an
JSON
document,
to
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s.
A
<dfn title="term" id="dfn-term">
term
</dfn>
is
a
short
word
that
expands
to
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
<a class="tref internalDFN" title="term" href="#dfn-term">
Term
</a>
s
<em class="rfc2119" title="may">
may
</em>
be
defined
as
any
valid
JSON
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
other
than
a
JSON-LD
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
To
avoid
forward-compatibility
issues,
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
starting
with
an
<code>
@
</code>
character
<em class="rfc2119" title="should not">
should
not
</em>
be
used
as
they
might
be
used
as
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keywords
</a>
in
future
versions
of
JSON-LD.
Furthermore,
the
use
of
empty
terms
(
<code>
&quot;&quot;
</code>
)
is
discouraged
as
not
all
programming
languages
are
able
to
handle
empty
property
names.
</p>
<p>
The
Web
uses
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>
for
unambiguous
identification.
The
idea
is
that
these
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
mean
something
that
may
be
of
use
to
other
developers
and
that
it
is
useful
to
give
them
an
unambiguous
identifier.
That
is,
it
is
useful
for
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
to
expand
to
IRIs
so
that
developers
don't
accidentally
step
on
each
other's
<dfn title="vocabulary" id="dfn-vocabulary">
vocabulary
</dfn>
<del class="diff-old">terms.
</del>
<ins class="diff-chg">terms
and
other
resources.
</ins>
Furthermore,
developers,
and
machines,
are
able
to
use
this
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(by
plugging
it
directly
into
a
web
browser,
for
instance)
to
go
to
the
term
and
get
a
definition
of
what
the
term
means.
This
mechanism
is
<del class="diff-old">analogousto
</del>
<ins class="diff-chg">analogous
to
</ins>
the
way
we
can
use
<a href="http://wordnet.princeton.edu/">
WordNet
</a>
today
to
see
the
definition
of
words
in
the
English
language.
Developers
and
machines
need
the
same
sort
of
definition
of
terms.
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>
provide
a
way
to
ensure
that
these
terms
are
unambiguous.
For
example,
the
term
<code>
name
</code>
may
map
directly
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
This
allows
JSON-LD
documents
to
be
constructed
using
the
common
JSON
practice
of
simple
name/value
pairs
while
ensuring
that
the
data
is
useful
outside
of
the
page,
API
or
database
in
which
it
resides.
The
value
of
a
term
mapping
<em class="rfc2119" title="must">
must
</em>
be
either;
1)
a
simple
string
with
the
lexical
form
of
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
2)
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
3)
an
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
an
<code>
@id
</code>,
<code>
@type
</code>,
<code>
@language
</code>,
or
<code>
@container
</code>
keyword
(all
other
keywords
are
ignored
by
a
JSON-LD
processor).
</p>
<p>
These
Linked
Data
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
are
typically
collected
in
a
context
document
that
would
look
something
like
this:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 2</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;depiction&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    },
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    },
  }
}
</pre>
</div>
<p>
Assuming
that
this
context
document
can
be
retrieved
at
<code>
<del class="diff-old">http://json-ld.org/contexts/person
</del>
<ins class="diff-chg">http://json-ld.org/contexts/person.jsonld
</ins>
</code>,
it
can
be
referenced
from
a
JSON-LD
document
by
adding
a
single
line.
The
JSON
markup
shown
in
the
previous
section
could
be
changed
as
follows:
</p>
<del class="diff-old">{
  
</del>
<div class="example"><div class="example-title"><span>Example 3</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;,</span>
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<p>
The
additions
above
transform
the
previous
JSON
document
into
a
JSON
document
with
added
semantics
because
the
<code>
@context
</code>
specifies
how
the
<strong>
name
</strong>,
<strong>
homepage
</strong>,
and
<strong>
depiction
</strong>
terms
map
to
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>.
Mapping
those
keys
to
IRIs
gives
the
data
global
context.
If
two
developers
use
the
same
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
to
describe
a
property,
they
are
more
than
likely
expressing
the
same
concept.
This
allows
both
developers
to
re-use
each
<del class="diff-old">others
</del>
<ins class="diff-chg">others'
</ins>
data
without
having
to
agree
to
how
their
data
will
interoperate
on
a
site-by-site
basis.
Contexts
may
also
contain
type
information
for
certain
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
as
well
as
other
processing
instructions
for
the
JSON-LD
processor.
</p>
<p>
Contexts
<em class="rfc2119" title="may">
may
</em>
be
specified
in-line.
This
ensures
that
JSON-LD
documents
can
be
processed
when
a
JSON-LD
processor
does
not
have
access
to
the
Web.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 4</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;depiction&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    },
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    },
  },</span>
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<p>
Contexts
<em class="rfc2119" title="may">
may
</em>
be
used
at
any
time
a
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
is
defined.
A
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
<em class="rfc2119" title="may">
may
</em>
specify
multiple
contexts,
using
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
which
is
processed
in
order.
This
is
useful
when
an
author
would
like
to
use
an
existing
context
and
add
application-specific
terms
to
the
existing
context.
Duplicate
context
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
<em class="rfc2119" title="must">
must
</em>
be
overridden
using
a
last-defined-overrides
mechanism.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
If
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
is
re-defined
within
a
context,
all
previous
rules
associated
with
the
previous
definition
are
removed.
A
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
defined
in
a
previous
context
<em class="rfc2119" title="must">
must
</em>
be
removed,
if
it
is
re-defined
to
<code>
null
</code>.
</p>
</div>
<p>
The
set
of
contexts
defined
within
a
specific
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
are
referred
to
as
<dfn title="local_context" id="dfn-local_context">
local
context
</dfn>
s.
Setting
the
context
to
<code>
null
</code>
effectively
sets
the
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
to
<del class="diff-old">its
</del>
<ins class="diff-chg">the
</ins>
initial
<del class="diff-old">state.
</del>
<ins class="diff-chg">context
(further
explained
in
the
JSON-LD
API,
Appendix
A,
Initial
Context
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API"><ins class="diff-chg">
JSON-LD-API
</ins></a></cite><ins class="diff-chg">
]
).
</ins>
The
<dfn title="active_context" id="dfn-active_context">
active
context
</dfn>
refers
to
the
accumulation
of
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
s
that
are
in
scope
at
a
specific
point
within
the
document.
The
following
example
specifies
an
external
context
and
then
layers
a
local
context
on
top
of
the
external
context:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 5</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;: [
<del class="diff-old">    &quot;http://json-ld.org/contexts/person&quot;,
</del>
<ins class="diff-chg">    &quot;http://json-ld.org/contexts/person.jsonld&quot;,
</ins>
    {
      &quot;pic&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;
    }
  ],</span>
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  <span class="diff">&quot;pic&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;</span>
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
To
ensure
the
best
possible
performance,
it
is
a
best
practice
to
put
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definition
at
the
top
of
the
JSON-LD
document.
If
it
isn't
listed
first,
processors
have
to
save
each
key-value
pair
until
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
is
processed.
This
creates
a
memory
and
complexity
burden
for
<del class="diff-old">one-pass
</del>
<ins class="diff-chg">certain
types
of
low-memory
footprint
JSON-LD
</ins>
processors.
</p>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class=""><ins class="diff-chg">
The
</ins><code><ins class="diff-chg">
null
</ins></code><ins class="diff-chg">
value
is
processed
in
a
special
way
in
JSON-LD.
Unless
otherwise
specified,
a
JSON-LD
processor
</ins><em class="rfc2119" title="must"><ins class="diff-chg">
must
</ins></em><ins class="diff-chg">
act
as
if
a
key-value
pair
in
the
body
of
a
JSON-LD
document
was
never
declared
when
the
value
equals
</ins><em><ins class="diff-chg">
null
</ins></em>.<ins class="diff-chg">
If
</ins><code><ins class="diff-chg">
@value
</ins></code>,<code><ins class="diff-chg">
@list
</ins></code>,<ins class="diff-chg">
or
</ins><code><ins class="diff-chg">
@set
</ins></code><ins class="diff-chg">
is
set
to
</ins><em><ins class="diff-chg">
null
</ins></em><ins class="diff-chg">
in
expanded
form,
then
the
entire
JSON
object
is
ignored.
If
</ins><code><ins class="diff-chg">
@context
</ins></code><ins class="diff-chg">
is
set
to
</ins><em><ins class="diff-chg">
null
</ins></em>,<ins class="diff-chg">
the
</ins><a class="tref internalDFN" title="active_context" href="#dfn-active_context"><ins class="diff-chg">
active
context
</ins></a><ins class="diff-chg">
is
reset
and
when
used
within
a
</ins><a class="tref internalDFN" title="context" href="#dfn-context"><ins class="diff-chg">
context
</ins></a>,<ins class="diff-chg">
it
removes
any
definition
associated
with
the
key,
unless
otherwise
specified.
</ins></p></div></div><div id="from-json-to-json-ld" class="section">
<h4>
<span class="secno">
<del class="diff-old">3.1.2
</del>
<ins class="diff-chg">3.1.3
</ins>
</span>
From
JSON
to
JSON-LD
</h4>
<p>
If
a
set
of
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
such
as,
<strong>
name
</strong>,
<strong>
homepage
</strong>,
and
<strong>
depiction
</strong>,
are
defined
in
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>,
and
that
context
is
used
to
resolve
the
names
in
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
<del class="diff-old">objects,
</del>
<ins class="diff-chg">objects
</ins></a>,
machines
are
able
to
automatically
expand
the
terms
to
something
meaningful
and
unambiguous,
like
this:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 6</span></div><pre class="example">{
  &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;: &quot;Manu Sporny&quot;,
  &quot;<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>&quot;: &quot;http://manu.sporny.org&quot;
  &quot;<span class="diff">http://xmlns.com/foaf/0.1/depiction</span>&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<p>
Doing
this
allows
JSON
to
be
unambiguously
machine-readable
without
requiring
developers
to
drastically
change
their
workflow.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
The
example
above
does
not
use
the
<code>
@id
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
to
set
the
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
of
the
node
being
described
above.
This
type
of
node
is
called
an
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
<del class="diff-old">and
is
considered
to
be
a
weaker
form
of
Linked
Data
</del>
</a>.
It
is
advised
that
all
nodes
described
in
JSON-LD
are
given
unique
identifiers
via
the
<code>
@id
</code>
keyword
unless
the
data
is
not
intended
to
be
linked
to
from
other
data
sets.
</p>
</div>
<p>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
define
property
values
is
called
a
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>.
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
Subject
definitions
</a>
do
not
require
<del class="diff-old">a
</del>
<ins class="diff-chg">an
</ins>
<code>
@id
<del class="diff-old">,
in
which
case
they
</del>
</code>.
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">Subject
definitions
</ins></a><ins class="diff-chg">
that
do
not
contain
an
</ins><code><ins class="diff-chg">
@id
</ins></code>
are
<del class="diff-old">considered
to
be
</del>
<ins class="diff-chg">known
as
</ins>
an
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
<del class="diff-old">node
</del>
<ins class="diff-chg">nodes
</ins>
</a>.
</p>
</div>
</div>
<div id="iris" class="section">
<h3>
<span class="secno">
3.2
</span>
IRIs
</h3>
<p>
<del class="diff-old">Expressing
</del>
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
are
fundamental
to
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
as
that
is
how
most
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
s,
all
<a class="tref internalDFN" title="property" href="#dfn-property">
properties
</a>
and
many
<a class="tref internalDFN" title="object" href="#dfn-object">
object
</a>
s
are
identified.
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
can
be
expressed
in
a
variety
of
different
ways
in
JSON-LD.
</p>
<ol>
<li>
Except
within
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definition,
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
in
the
key
position
in
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
that
have
a
mapping
to
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
another
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
are
expanded
to
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
by
JSON-LD
processors.
</li>
<li>
An
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
value
specified
using
<code>
@id
</code>
or
<code>
@type
</code>.
</li>
<li>
An
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
for
the
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
value
of
any
key
for
which
there
are
<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
coercion
</a>
rules
in
effect
that
identify
the
value
as
an
<code>
@id
</code>.
</li>
</ol>
<p>
IRIs
may
be
represented
as
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
or
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<p>
An
<dfn title="absolute_iri" id="dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
defined
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC3987">
RFC3987
</a>
</cite>
]
containing
a
<em>
scheme
</em>
along
with
<em>
path
</em>
and
optional
<em>
query
</em>
and
<em>
fragment
</em>
segments.
A
<dfn title="relative_iri" id="dfn-relative_iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
that
is
relative
<ins class="diff-new">to
</ins>
some
other
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
In
JSON-LD
all
<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
are
resolved
relative
to
the
<dfn title="base_iri" id="dfn-base_iri">
base
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
associated
with
the
document
(typically,
the
directory
that
contains
the
document
or
the
document
itself).
</p>
<p>
IRIs
can
be
expressed
directly
in
the
key
position
like
so:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 7</span></div><pre class="example">{
...
  &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;: &quot;Manu Sporny&quot;,
...
}
</pre>
</div>
<p>
In
the
example
above,
the
key
<code>
http://xmlns.com/foaf/0.1/name
</code>
is
interpreted
as
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<del class="diff-old">,
as
opposed
to
being
interpreted
as
a
string
</del>
</a>
because
it
contains
a
colon
(
<code>:
</code>
)
<del class="diff-old">delimiting
a
valid
IRI
scheme.
</del>
<ins class="diff-chg">and
the
'http'
</ins><a class="tref internalDFN" title="prefix" href="#dfn-prefix"><ins class="diff-chg">
prefix
</ins></a><ins class="diff-chg">
does
not
exist
in
the
context.
</ins>
</p>
<p>
Term
expansion
occurs
for
IRIs
if
the
value
matches
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
defined
within
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 8</span></div><pre class="example">{
  &quot;<span class="diff">@context</span>&quot;:
  {
    &quot;<span class="diff">name</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;
...
  },
  &quot;<span class="diff">name</span>&quot;: &quot;Manu Sporny&quot;,
  &quot;status&quot;: &quot;trollin'&quot;,
...
}
</pre>
</div>
<p>
<a class="tref internalDFN" title="term" href="#dfn-term">
Term
</a>
s
are
case
sensitive,
and
<em class="rfc2119" title="must">
must
</em>
be
matched
using
a
case-sensitive
comparison.
</p>
<p>
JSON
keys
that
do
not
expand
to
an
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
are
ignored,
or
removed
in
some
cases,
by
the
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
JSON-LD-API
</a>
</cite>
].
However,
JSON
keys
that
do
not
include
a
mapping
in
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
are
still
considered
valid
expressions
in
JSON-LD
documents
-
the
keys
just
don't
have
any
machine-readable,
semantic
meaning.
</p>
<p>
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
Prefix
</a>
es
are
expanded
when
the
form
of
the
value
is
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
represented
as
a
<code>
prefix:suffix
</code>
combination,
and
the
prefix
matches
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
defined
within
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 9</span></div><pre class="example">{
  &quot;<span class="diff">@context</span>&quot;:
  {
    &quot;<span class="diff">foaf</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/</span>&quot;
...
  },
  &quot;<span class="diff">foaf:name</span>&quot;: &quot;Manu Sporny&quot;,
...
}
</pre>
</div>
<p>
<code>
foaf:name
</code>
above
will
automatically
expand
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
See
<a href="#compact-iris">
Compact
IRIs
</a>
for
more
details.
</p>
<p>
An
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
generated
when
a
JSON
object
is
used
in
the
value
position
that
contains
an
<code>
@id
</code>
keyword:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 10</span></div><pre class="example">{
...
  &quot;homepage&quot;: { &quot;<span class="diff">@id</span>&quot;: &quot;http://manu.sporny.org&quot; }
...
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
Specifying
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
with
an
<code>
@id
</code>
key
is
used
to
identify
that
object
using
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
<ins class="diff-new">When
the
object
has
only
the
</ins><code><ins class="diff-new">
@id
</ins></code>,<ins class="diff-new">
it
is
called
a
</ins><a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference"><ins class="diff-new">
subject
reference
</ins></a>.
This
facility
<em class="rfc2119" title="may">
may
</em>
also
be
used
to
link
to
another
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
using
a
mechanism
called
<a class="tref internalDFN" title="embedding" href="#dfn-embedding">
embedding
</a>,
which
is
covered
in
the
section
titled
<a href="#embedding">
Embedding
</a>.
</p>
</div>
<p>
If
type
<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
coercion
</a>
rules
are
specified
in
the
<code>
@context
</code>
for
a
particular
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
or
property
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated:
</p>
<div class="example"><div class="example-title"><span>Example 11</span></div><pre class="example">{<span class="diff">
  &quot;@context&quot;:
  {
    ...
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
    ...
  }</span>
...
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
...
}
</pre>
</div>
<p>
In
the
example
above,
even
though
the
value
<code>
http://manu.sporny.org/
</code>
is
expressed
as
a
JSON
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>,
the
type
<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
coercion
</a>
rules
will
transform
the
value
into
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
when
processed
by
a
JSON-LD
Processor.
</p>
</div>
<div id="identifying-the-subject" class="section">
<h3>
<span class="secno">
3.3
</span>
Identifying
the
Subject
</h3>
<p>
To
be
able
to
externally
reference
nodes
in
a
graph,
it
is
important
that
each
node
has
an
unambiguous
identifier.
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
are
a
fundamental
concept
of
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>,
and
nodes
should
have
a
de-referencable
identifier
used
to
name
and
locate
them.
For
nodes
to
be
truly
linked,
de-referencing
the
identifier
should
result
in
a
representation
of
that
node
(for
example,
using
a
URL
to
retrieve
a
web
page).
Associating
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
with
a
node
tells
an
application
that
the
returned
document
contains
a
description
of
the
node
requested.
</p>
<p>
JSON-LD
documents
may
also
contain
descriptions
of
other
nodes,
so
it
is
necessary
to
be
able
to
uniquely
identify
each
node
which
may
be
externally
referenced.
</p>
<p>
A
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
of
<del class="diff-old">an
object
in
</del>
<ins class="diff-chg">a
</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
<ins class="diff-new">object
</ins></a>
is
<del class="diff-old">declared
</del>
<ins class="diff-chg">a
node
identified
</ins>
using
the
<code>
@id
</code>
key.
The
subject
is
the
first
piece
of
information
needed
by
the
JSON-LD
processor
in
order
to
create
the
(subject,
property,
object)
tuple,
also
known
as
a
triple.
</p>
<del class="diff-old">{
...
</del>
<div class="example"><div class="example-title"><span>Example 12</span></div><pre class="example">{
<ins class="diff-chg">  &quot;@context&quot;:
  {
    ...
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
    ...
  },
</ins>
  &quot;<span class="diff">@id</span>&quot;: &quot;<span class="diff">http://example.org/people#joebob</span>&quot;,
<ins class="diff-new">  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
</ins>
...
}
</pre>
</div>
<p>
The
example
above
would
set
the
subject
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://example.org/people#joebob
</code>.
</p>
<p>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
used
to
define
property
values
is
called
a
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>.
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
Subject
definitions
</a>
do
not
require
an
<code>
@id
</code>.
A
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>
that
does
not
contain
an
<code>
@id
</code>
property
<del class="diff-old">is
called
</del>
<ins class="diff-chg">defines
properties
of
</ins>
an
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
</a>.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
To
ensure
the
best
possible
performance,
<ins class="diff-new">when
possible,
</ins>
it
is
a
best
practice
to
put
<del class="diff-old">the
@id
</del>
<ins class="diff-chg">JSON-LD
</ins>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
<ins class="diff-new">s,
such
as
</ins><code><ins class="diff-new">
@id
</ins></code><ins class="diff-new">
and
</ins><code><ins class="diff-new">
@context
</ins></code>
before
other
key-value
pairs
in
<del class="diff-old">an
object.
</del>
<ins class="diff-chg">a
</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
JSON
object
</ins></a>.<ins class="diff-chg">
However,
keys
in
a
</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
JSON
object
</ins></a><ins class="diff-chg">
are
not
ordered,
so
processors
</ins><em class="rfc2119" title="must not"><ins class="diff-chg">
must
not
</ins></em><ins class="diff-chg">
depend
on
key
ordering.
</ins>
If
<del class="diff-old">it
isn't
</del>
<ins class="diff-chg">keywords
are
not
</ins>
listed
first,
processors
have
to
save
each
key-value
pair
until
<ins class="diff-new">at
least
the
</ins>
<code>
<del class="diff-old">@id
</del>
<ins class="diff-chg">@context
</ins>
</code>
<del class="diff-old">is
processed
before
they
can
start
generating
triples.
Not
specifying
</del>
<ins class="diff-chg">and
</ins>
the
<code>
@id
</code>
<del class="diff-old">keyword
</del>
<ins class="diff-chg">are
processed.
Not
specifying
those
keywords
</ins>
first
creates
a
memory
and
complexity
burden
for
<del class="diff-old">one-pass
processors.
</del>
<ins class="diff-chg">low-memory
footprint
processors,
forcing
them
to
use
more
memory
and
computing
cycles
than
necessary.
</ins>
</p>
</div>
</div>
<div id="specifying-the-type" class="section">
<h3>
<span class="secno">
3.4
</span>
Specifying
the
Type
</h3>
<p>
The
type
of
a
particular
subject
can
be
specified
using
the
<code>
@type
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
Specifying
the
type
in
this
way
will
generate
a
triple
of
the
form
(subject,
type,
type-
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
).
To
be
considered
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>,
types
<em class="rfc2119" title="must">
must
</em>
be
uniquely
identified
by
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 13</span></div><pre class="example">{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;<span class="diff">@type</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/Person</span>&quot;,
...
}
</pre>
</div>
</div>
<div id="string-internationalization" class="section">
<h3>
<span class="secno">
3.5
</span>
String
Internationalization
</h3>
<p>
At
times,
it
is
important
to
annotate
a
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
with
its
language.
In
JSON-LD
this
is
possible
in
a
variety
of
ways.
Firstly,
it
is
possible
to
define
a
default
language
for
a
JSON-LD
document
by
setting
the
<code>
@language
</code>
key
in
the
<code>
@context
</code>
or
in
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
definition:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 14</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;:
  {
    ...
    &quot;@language&quot;: &quot;ja&quot;
  },</span>
  &quot;name&quot;: <span class="diff">&quot;花澄&quot;</span>,
  &quot;occupation&quot;: <span class="diff">&quot;科学者&quot;</span>
}
</pre>
</div>
<p>
The
example
above
would
associate
the
<code>
ja
</code>
language
code
with
the
two
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
s
<em>
花澄
</em>
and
<em>
科学者
</em>.
Languages
<em class="rfc2119" title="must">
must
</em>
be
<del class="diff-old">expressed
in
</del>
<ins class="diff-chg">well-formed
language
tags
according
to
</ins>
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-BCP47">
BCP47
</a>
</cite>
<del class="diff-old">]
format.
</del>
<ins class="diff-chg">].
</ins>
</p>
<p>
It
is
possible
to
override
the
default
language
by
using
the
expanded
form
of
a
value:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 15</span></div><pre class="example">{
  &quot;@context&quot;: {
    ...
    &quot;@language&quot;: &quot;ja&quot;
  },
  &quot;name&quot;: &quot;花澄&quot;,
  &quot;occupation&quot;: <span class="diff">{
    &quot;@value&quot;: &quot;Scientist&quot;,
    &quot;@language&quot;: &quot;en&quot;
  }</span>
}
</pre>
</div>
<p>
It
is
also
possible
to
override
the
default
language
or
specify
a
plain
value
by
omitting
the
<code>
@language
</code>
tag
or
setting
it
to
<code>
null
</code>
when
expressing
the
expanded
value:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 16</span></div><pre class="example">{
  &quot;@context&quot;: {
    ...
    &quot;@language&quot;: &quot;ja&quot;
  },
  &quot;name&quot;: <span class="diff">{
    &quot;@value&quot;: &quot;Frank&quot;
  },</span>
  &quot;occupation&quot;: <span class="diff"> {
    &quot;@value&quot;: &quot;Ninja&quot;,
    &quot;@language&quot;: &quot;en&quot;
  }</span>,
  &quot;speciality&quot;: &quot;手裏剣&quot;
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
Please
note
that
language
associations
<em class="rfc2119" title="must">
must
</em>
only
be
applied
to
plain
literal
<a class="tref internalDFN" title="string" href="#dfn-string">
string
</a>
s.
That
is,
<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
typed
value
</a>
s
or
values
that
are
subject
to
<a href="#type-coercion">
type
coercion
</a>
won't
be
language
tagged.
</p>
</div>
<p>
To
clear
the
default
language
for
a
subtree,
<code>
@language
</code>
can
be
set
to
<code>
null
</code>
in
a
<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
local
context
</a>
as
follows:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 17</span></div><pre class="example">{
  &quot;@context&quot;: {
    ...
    &quot;@language&quot;: &quot;ja&quot;
  },
  &quot;name&quot;: &quot;花澄&quot;,
  &quot;details&quot;: {
<span class="diff">    &quot;@context&quot;: {
      &quot;@language&quot;: null
    },</span>
    &quot;occupation&quot;: &quot;Ninja&quot;
  }
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
JSON-LD
allows
one
to
associate
language
information
with
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s.
See
<a href="#expanded-term-definition">
Expanded
Term
Definition
</a>
for
more
details.
</p>
</div>
</div>
<div id="json-ld-syntax" class="section">
<h3>
<span class="secno">
3.6
</span>
<del class="diff-old">Sets
and
Lists
</del>
<ins class="diff-chg">JSON-LD
Syntax
</ins>
</h3>
<p>
A
JSON-LD
<del class="diff-old">author
can
express
multiple
values
in
a
compact
way
by
using
array
s.
Since
graphs
do
not
describe
ordering
for
links
between
nodes,
arrays
in
JSON-LD
do
not
provide
an
ordering
of
the
listed
objects
by
default.
This
is
exactly
the
opposite
from
regular
JSON
arrays,
which
are
ordered
by
default.
For
example,
consider
the
following
simple
document:
{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: ,
...
}
The
markup
shown
above
would
result
in
three
triples
being
generated,
each
relating
the
subject
to
an
individual
object,
with
no
inherent
order:
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;joe&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;bob&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
&quot;jaybee&quot;
.
Multiple
values
may
also
be
expressed
using
the
expanded
object
form:
{
  &quot;@id&quot;: &quot;http://example.org/articles/8&quot;,
  &quot;dc:title&quot;: 
  [
    {
      &quot;@value&quot;: &quot;Das Kapital&quot;,
      &quot;@language&quot;: &quot;de&quot;
    },
    {
      &quot;@value&quot;: &quot;Capital&quot;,
      &quot;@language&quot;: &quot;en&quot;
    }
  ]
}
The
markup
shown
above
would
generate
the
following
triples,
again
with
no
inherent
order:
&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
      &quot;Das Kapital&quot;@de .
&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
&quot;Capital&quot;@en
.
As
the
notion
of
ordered
collections
is
rather
important
in
data
modeling,
it
</del>
<ins class="diff-chg">document
</ins>
is
<del class="diff-old">useful
to
have
specific
language
support.
In
JSON-LD,
a
list
may
be
represented
using
the
@list
keyword
as
follows:
{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;foaf:nick&quot;:
  {
    &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]
  },
...
}
This
describes
the
use
of
this
array
as
being
ordered,
</del>
<ins class="diff-chg">first,
</ins>
and
<del class="diff-old">order
is
maintained
when
processing
a
document.
If
every
use
of
a
given
multi-valued
property
is
</del>
<ins class="diff-chg">foremost,
</ins>
a
<del class="diff-old">list,
this
may
be
abbreviated
by
setting
@container
to
@list
in
the
context
:
{
  &quot;@context&quot;:
  {
    ...
    &quot;nick&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/nick&quot;,
      &quot;@container&quot;: &quot;@list&quot;
    }
  },
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: ,
...
}
List
of
lists
are
not
allowed
</del>
<ins class="diff-chg">JSON
document
(as
defined
</ins>
in
<del class="diff-old">this
version
of
JSON-LD.
If
a
list
of
lists
is
detected,
a
JSON-LD
processor
will
throw
an
exception.
This
decision
was
made
due
to
the
extreme
amount
of
added
complexity
when
processing
lists
of
lists.
Similarly
to
@list
,
there
exists
the
keyword
</del>
<ins class="diff-chg">[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RFC5988"><ins class="diff-chg">
RFC5988
</ins>
</a>
<del class="diff-old">@set
to
describe
unordered
sets.
While
its
use
in
the
body
of
a
JSON-LD
</del>
</cite>
<ins class="diff-chg">]),
and
any
syntactically
correct
JSON
</ins>
document
<del class="diff-old">represents
just
syntactic
sugar
that
</del>
<em class="rfc2119" title="must">
must
</em>
be
<del class="diff-old">optimized
away
when
processing
the
document,
it
is
very
helpful
when
used
within
the
context
of
a
document.
Values
of
terms
associated
with
</del>
<ins class="diff-chg">processed
by
</ins>
a
<del class="diff-old">@set
or
@list
container
are
always
represented
in
the
form
of
an
array
-
even
if
there
is
just
</del>
<ins class="diff-chg">conforming
JSON-LD
processor.
However,
JSON-LD
describes
</ins>
a
<del class="diff-old">single
value
that
would
otherwise
be
optimized
</del>
<ins class="diff-chg">specific
syntax
</ins>
to
<del class="diff-old">a
non-array
form
in
a
compacted
document
.
</del>
<ins class="diff-chg">use
for
expressing
Linked
Data.
</ins>
This
<del class="diff-old">makes
post-processing
of
the
data
easier
as
the
data
is
always
in
array
form,
even
if
</del>
<ins class="diff-chg">includes
</ins>
the
<del class="diff-old">array
only
contains
a
single
value.
The
</del>
use
of
<del class="diff-old">@container
</del>
<ins class="diff-chg">specific
keywords,
as
identified
</ins>
in
<a href="#syntax-tokens-and-keywords">
<ins class="diff-new">Syntax
Tokens
and
Keywords
</ins></a><ins class="diff-new">
for
expressing
</ins><a title="subject definition"><ins class="diff-new">
subject
definitions
</ins></a>,<ins class="diff-new">
values,
and
</ins>
the
<del class="diff-old">body
of
</del>
<a href="#dfn-context" class="internalDFN">
<ins class="diff-chg">context
</ins></a>.<ins class="diff-chg">
See
</ins><a href="#json-ld-authoring-guidelines"><ins class="diff-chg">
Appendix
A
</ins></a><ins class="diff-chg">
for
authoring
guidelines
and
</ins>
a
<del class="diff-old">JSON-LD
document,
i.e.,
outside
@context
must
be
ignored
by
JSON-LD
processors.
</del>
<ins class="diff-chg">BNF
description
of
JSON-LD.
</ins>
</p>
</div>
</div>
<div id="advanced-concepts" class="section">
<h2>
<span class="secno">
4.
</span>
Advanced
Concepts
</h2>
<em>
<ins class="diff-new">This
section
is
normative.
</ins></em>
<p>
JSON-LD
has
a
number
of
features
that
provide
functionality
above
and
beyond
the
core
functionality
described
above.
The
following
section
describes
this
advanced
functionality
in
more
detail.
</p>
<div id="compact-iris" class="section">
<h3>
<span class="secno">
4.1
</span>
<del class="diff-old">Typed
Values
A
value
with
an
associated
type,
also
known
as
a
typed
value
,
is
indicated
by
associating
a
value
with
an
IRI
which
indicates
the
value's
type.
Typed
values
may
be
expressed
in
JSON-LD
in
three
ways:
By
utilizing
the
@type
keyword
when
defining
a
term
within
a
@context
section.
By
utilizing
the
expanded
form
for
specifying
objects.
By
using
a
native
JSON
type.
The
first
example
uses
the
@type
keyword
to
associate
a
type
with
a
particular
term
in
the
@context
:
{
  &quot;@context&quot;:
  {
    &quot;modified&quot;:
    {
      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;,
      &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#dateTime&quot;
    }
  },
...
  &quot;modified&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
...
}
The
modified
key's
value
above
is
automatically
type
coerced
to
a
datetime
value
because
of
the
information
specified
in
the
@context
.
The
second
example
uses
the
expanded
form
of
setting
the
type
information
in
the
body
of
a
JSON-LD
document:
{
  &quot;@context&quot;:
  {
    &quot;modified&quot;:
    {
      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;
    }
  },
...
  &quot;modified&quot;:
  {
    &quot;@value&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#dateTime&quot;
  }
...
}
Both
examples
above
would
generate
an
object
with
the
value
of
2010-05-29T14:17:39+02:00
and
the
type
of
http://www.w3.org/2001/XMLSchema#dateTime
.
The
third
example
uses
a
built-in
native
JSON
type,
a
number
,
to
express
a
type:
{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;age&quot;: 
...
}
The
example
above
is
really
just
a
shorthand
for
the
following:
{
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;age&quot;:
  {
    &quot;@value&quot;: &quot;31&quot;,
    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#integer&quot;
  }
...
}
The
@type
keyword
is
also
used
to
associate
a
type
with
a
subject
.
Although
the
same
keyword
is
used
in
both
places,
the
concept
of
an
object
type
and
a
value
type
are
different.
This
is
similar
to
object-oriented
programming
languages
where
both
scalar
and
structured
types
use
the
same
class
inheritance
mechanism,
even
though
scalar
types
and
structured
types
are
inherently
different.
4.2
</del>
Compact
IRIs
</h3>
<p>
<a class="tref internalDFN" title="term" href="#dfn-term">
Term
</a>
s
in
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
documents
may
draw
from
a
number
of
different
<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
vocabularies
</a>.
At
times,
declaring
every
single
term
that
a
document
uses
can
require
the
developer
to
declare
tens,
if
not
hundreds
of
potential
<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
vocabulary
</a>
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
that
are
used
across
an
application.
This
is
a
concern
for
at
least
two
reasons:
the
first
is
the
cognitive
load
on
the
developer
of
remembering
all
of
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s,
and
the
second
is
the
serialized
size
of
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
if
it
is
specified
inline.
In
order
to
address
these
issues,
the
concept
of
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
introduced.
</p>
<p>
A
<dfn title="compact_iri" id="dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</dfn>
is
a
way
of
expressing
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
using
a
<em>
prefix
</em>
and
<em>
suffix
</em>
separated
by
a
colon
(
<code>:
</code>
)
which
is
similar
to
the
<cite>
<a href="http://www.w3.org/TR/rdfa-core/#s_curies">
CURIE
Syntax
</a>
</cite>
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDFA-CORE">
RDFA-CORE
</a>
</cite>
].
The
<dfn title="prefix" id="dfn-prefix">
prefix
</dfn>
is
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
taken
from
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
and
is
a
short
string
identifying
a
particular
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
in
a
JSON-LD
document.
For
example,
the
prefix
<code>
foaf
</code>
may
be
used
as
a
short
hand
for
the
Friend-of-a-Friend
vocabulary,
which
is
identified
using
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/
</code>.
A
developer
may
append
any
of
the
FOAF
<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
vocabulary
</a>
terms
to
the
end
of
the
prefix
to
specify
a
short-hand
version
of
the
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
vocabulary
</a>
term.
For
example,
<code>
foaf:name
</code>
would
be
expanded
out
to
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
http://xmlns.com/foaf/0.1/name
</code>.
Instead
of
having
to
remember
and
type
out
the
entire
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
the
developer
can
instead
use
the
prefix
in
their
JSON-LD
markup.
</p>
<p>
Terms
are
interpreted
as
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
if
they
contain
at
least
one
colon
and
the
first
colon
is
not
followed
by
two
slashes
(
<code>
//
</code>,
as
in
<code>
http://example.com
</code>
).
To
generate
the
full
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
the
value
is
first
split
into
a
<em>
prefix
</em>
and
<em>
suffix
</em>
at
the
first
occurrence
of
a
colon
(
<code>:
</code>
).
If
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>
contains
a
term
mapping
for
<em>
prefix
</em>,
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
generated
by
prepending
the
mapped
<em>
prefix
</em>
to
the
(possibly
empty)
<em>
suffix
</em>
using
textual
concatenation.
If
no
prefix
mapping
is
defined,
the
value
is
interpreted
as
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
If
the
prefix
is
an
underscore
(
<code>
_
</code>
),
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
remains
unchanged.
This
effectively
means
that
every
term
containing
a
colon
will
be
interpreted
by
a
JSON-LD
processor
as
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
</p>
<p>
Consider
the
following
example:
</p>
<del class="diff-old">  {
</del>
  <div class="example"><div class="example-title"><span>Example 18</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;dc&quot;: &quot;http://purl.org/dc/elements/1.1/&quot;,</span>
    <span class="diff">&quot;ex&quot;: &quot;http://example.org/vocab#&quot;</span>
  },
  &quot;@id&quot;: &quot;http://example.org/library&quot;,
  &quot;@type&quot;: <span class="diff">&quot;ex:Library&quot;</span>,
  <span class="diff">&quot;ex:contains&quot;</span>:
  {
    &quot;@id&quot;: &quot;http://example.org/library/the-republic&quot;,
    &quot;@type&quot;: <span class="diff">&quot;ex:Book&quot;</span>,
    <span class="diff">&quot;dc:creator&quot;</span>: &quot;Plato&quot;,
    <span class="diff">&quot;dc:title&quot;</span>: &quot;The Republic&quot;,
    <span class="diff">&quot;ex:contains&quot;</span>:
    {
      &quot;@id&quot;: &quot;http://example.org/library/the-republic#introduction&quot;,
      &quot;@type&quot;: <span class="diff">&quot;ex:Chapter&quot;</span>,
      <span class="diff">&quot;dc:description&quot;</span>: &quot;An introductory chapter on The Republic.&quot;,
      <span class="diff">&quot;dc:title&quot;</span>: &quot;The Introduction&quot;
    }
  }
}
</pre>
</div>
<p>
In
this
example,
two
different
<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
vocabularies
</a>
are
referred
to
using
prefixes.
Those
prefixes
are
then
used
as
type
and
property
values
using
the
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<code>
prefix:suffix
</code>
notation.
</p>
<p>
It's
also
possible
to
use
compact
IRIs
within
the
context
as
shown
in
the
following
example:
</p>
<del class="diff-old">  {
</del>
  <div class="example"><div class="example-title"><span>Example 19</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
    <span class="diff">&quot;foaf:homepage&quot;</span>: { &quot;@type&quot;: &quot;@id&quot; },
    &quot;picture&quot;: { &quot;@id&quot;: <span class="diff">&quot;foaf:depiction&quot;</span>, &quot;@type&quot;: &quot;@id&quot; }
  },
<del class="diff-old">  &quot;@subject&quot;: &quot;http://me.markus-lanthaler.com/&quot;,
</del>
<ins class="diff-chg">  &quot;@id&quot;: &quot;http://me.markus-lanthaler.com/&quot;,
</ins>
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Markus Lanthaler&quot;,
  &quot;foaf:homepage&quot;: &quot;http://www.markus-lanthaler.com/&quot;,
  &quot;picture&quot;: &quot;http://twitter.com/account/profile_image/markuslanthaler&quot;
}
</pre>
</div>
</div>
<div id="typed-values" class="section">
<h3>
<span class="secno">
<ins class="diff-chg">4.2
</ins></span><ins class="diff-chg">
Typed
Values
</ins></h3><p><ins class="diff-chg">
A
value
with
an
associated
type,
also
known
as
a
</ins><dfn title="typed_value" id="dfn-typed_value"><ins class="diff-chg">
typed
value
</ins></dfn>,<ins class="diff-chg">
is
indicated
by
associating
a
value
with
an
</ins><a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
which
indicates
the
value's
type.
Typed
values
may
be
expressed
in
JSON-LD
in
two
ways:
</ins></p><ol><li><ins class="diff-chg">
By
utilizing
the
</ins><code><ins class="diff-chg">
@type
</ins></code><a class="tref internalDFN" title="keyword" href="#dfn-keyword"><ins class="diff-chg">
keyword
</ins></a><ins class="diff-chg">
when
defining
a
</ins><a class="tref internalDFN" title="term" href="#dfn-term"><ins class="diff-chg">
term
</ins></a><ins class="diff-chg">
within
a
</ins><code><ins class="diff-chg">
@context
</ins></code><ins class="diff-chg">
section.
</ins></li><li><ins class="diff-chg">
By
utilizing
the
expanded
form
for
specifying
objects.
</ins></li></ol><p><ins class="diff-chg">
The
first
example
uses
the
</ins><code><ins class="diff-chg">
@type
</ins></code><ins class="diff-chg">
keyword
to
associate
a
type
with
a
particular
</ins><a class="tref internalDFN" title="term" href="#dfn-term"><ins class="diff-chg">
term
</ins></a><ins class="diff-chg">
in
the
</ins><code><ins class="diff-chg">
@context
</ins></code>:</p><div class="example"><div class="example-title"><span>Example 20</span></div><pre class="example">{  <span class="diff">&quot;@context&quot;:<ins class="diff-chg">
  {
    &quot;modified&quot;:
    {
      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;,
      &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#dateTime&quot;
    }
  },</span>
...
  &quot;modified&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
...
}
</ins></pre></div><p><ins class="diff-chg">
The
</ins><em><ins class="diff-chg">
modified
</ins></em><ins class="diff-chg">
key's
value
above
is
automatically
type
coerced
to
a
datetime
value
because
of
the
information
specified
in
the
</ins><code><ins class="diff-chg">
@context
</ins></code>.</p><p><ins class="diff-chg">
The
second
example
uses
the
expanded
form
of
setting
the
type
information
in
the
body
of
a
JSON-LD
document:
</ins></p><div class="example"><div class="example-title"><span>Example 21</span></div><pre class="example">{<ins class="diff-chg">
  &quot;@context&quot;:
  {
    &quot;modified&quot;:
    {
      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;
    }
  },
...
  &quot;modified&quot;:
</ins>  <span class="diff">{<ins class="diff-chg">
    &quot;@value&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#dateTime&quot;
  }</span>
...
}
</ins></pre></div><p><ins class="diff-chg">
Both
examples
above
would
generate
an
object
with
the
value
of
</ins><code><ins class="diff-chg">
2010-05-29T14:17:39+02:00
</ins></code><ins class="diff-chg">
and
the
type
of
</ins><code><ins class="diff-chg">
http://www.w3.org/2001/XMLSchema#dateTime
</ins></code>.<ins class="diff-chg">
Note
that
it
is
also
possible
to
use
a
</ins><a class="tref internalDFN" title="term" href="#dfn-term"><ins class="diff-chg">
term
</ins></a><ins class="diff-chg">
or
a
</ins><a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri"><ins class="diff-chg">
compact
</ins><abbr title="Internationalized Resource Identifier"><ins class="diff-chg">
IRI
</ins></abbr></a><ins class="diff-chg">
to
express
the
value
of
a
type.
</ins></p><div class="note"><div class="note-title"><span><ins class="diff-chg">
Note
</ins></span></div><p class=""><ins class="diff-chg">
The
</ins><code><ins class="diff-chg">
@type
</ins></code><a class="tref internalDFN" title="keyword" href="#dfn-keyword"><ins class="diff-chg">
keyword
</ins></a><ins class="diff-chg">
is
also
used
to
associate
a
type
with
a
</ins><a class="tref internalDFN" title="subject" href="#dfn-subject"><ins class="diff-chg">
subject
</ins></a>.<ins class="diff-chg">
Although
the
same
keyword
is
used
in
both
places,
the
concept
of
an
</ins><em><ins class="diff-chg">
object
type
</ins></em><ins class="diff-chg">
and
a
</ins><em><ins class="diff-chg">
value
type
</ins></em><ins class="diff-chg">
are
different.
This
is
similar
to
object-oriented
programming
languages
where
both
scalar
and
structured
types
use
the
same
class
inheritance
mechanism,
even
though
scalar
types
and
structured
types
are
inherently
different.
</ins></p></div></div><div id="external-contexts" class="section">
<h3>
<span class="secno">
4.3
</span>
External
Contexts
</h3>
<p>
Authors
may
choose
to
declare
JSON-LD
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
s
in
external
documents
to
promote
re-use
of
contexts
as
well
as
reduce
the
size
of
JSON-LD
documents.
</p>
<p>
In
order
to
use
an
external
context,
an
author
<em class="rfc2119" title="must">
must
</em>
specify
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
a
valid
JSON-LD
document.
The
referenced
document
<em class="rfc2119" title="must">
must
</em>
have
a
top-level
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>.
The
value
of
any
<code>
@context
</code>
key
within
that
object
is
substituted
for
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
within
the
referencing
document
to
have
the
same
effect
as
if
the
value
were
specified
inline
within
the
referencing
document.
</p>
<p>
The
following
example
demonstrates
the
use
of
an
external
context:
</p>
<del class="diff-old">{
  ,
</del>
<div class="example"><div class="example-title"><span>Example 22</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;: &quot;http://json-ld.org/contexts/person.jsonld&quot;</span>,
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<p>
Authors
may
also
import
multiple
contexts
or
a
combination
of
external
and
local
contexts
by
specifying
a
list
of
contexts:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 23</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;:
  [
<del class="diff-old">    &quot;http://json-ld.org/contexts/person&quot;,
</del>
<ins class="diff-chg">    &quot;http://json-ld.org/contexts/person.jsonld&quot;,
</ins>
    {
      &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
    },
<del class="diff-old">    &quot;http://json-ld.org/contexts/event&quot;,
  ]
</del>
<ins class="diff-chg">    &quot;http://json-ld.org/contexts/event.jsonld&quot;
  ],</span>
</ins>
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
<del class="diff-old">  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
</del>
<ins class="diff-chg">  &quot;foaf:depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;,
</ins>
  <span class="diff">&quot;celebrates&quot;:
  {
    &quot;@type&quot;: &quot;Event&quot;,
    &quot;description&quot;: &quot;International Talk Like a Pirate Day&quot;,
    &quot;date&quot;: &quot;R/2011-09-19&quot;
  }</span>
}
</pre>
</div>
<p>
Each
context
in
a
list
will
be
evaluated
in-order.
Duplicate
mappings
among
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
s
<em class="rfc2119" title="must">
must
</em>
be
overwritten
on
a
last-defined-overrides
basis.
The
context
list
<em class="rfc2119" title="must">
must
</em>
contain
either
de-referenceable
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
or
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
s
that
conform
to
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
syntax
as
described
in
this
document.
</p>
<p>
An
author
<em class="rfc2119" title="may">
may
</em>
nest
contexts
within
<del class="diff-old">JSON
object
s,
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definitions
</ins></a>,
with
the
more
deeply
nested
contexts
overriding
the
values
in
previously
defined
contexts:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 24</span></div><pre class="example">{
  <span class="diff">&quot;@context&quot;:
  {
    &quot;name&quot;: &quot;http://example.com/person#name&quot;,
    &quot;details&quot;: &quot;http://example.com/person#details&quot;
  },</span>
  &quot;<span class="diff">name</span>&quot;: &quot;Markus Lanthaler&quot;,
  ...
  &quot;details&quot;:
  {
    <span class="diff">&quot;@context&quot;: {
      &quot;name&quot;: &quot;http://example.com/organization#name&quot;
    },</span>
    &quot;<span class="diff">name</span>&quot;: &quot;Graz University of Technology&quot;
  }
}
</pre>
</div>
<p>
In
the
example
above,
the
<code>
name
</code>
prefix
is
overridden
in
the
more
deeply
nested
<code>
details
</code>
structure.
Note
that
this
is
rarely
a
good
authoring
practice
and
is
typically
used
when
the
JSON
object
has
legacy
applications
using
the
structure
of
the
object.
</p>
<p>
External
JSON-LD
context
documents
<em class="rfc2119" title="may">
may
</em>
contain
extra
information
located
outside
of
the
<code>
@context
</code>
key,
such
as
documentation
about
the
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefixes
</a>
declared
in
the
document.
When
importing
a
<code>
@context
</code>
value
from
an
external
JSON-LD
context
document,
any
extra
information
contained
outside
of
the
<code>
@context
</code>
value
<em class="rfc2119" title="must">
must
</em>
be
discarded.
It
is
also
<em class="rfc2119" title="recommended">
recommended
</em>
that
a
human-readable
document
is
served
as
well
to
explain
the
correct
usage
of
the
JSON-LD
context
document.
</p>
</div>
<div id="referencing-contexts-from-json-documents" class="section">
<h3>
<span class="secno">
4.4
</span>
Referencing
Contexts
from
JSON
Documents
</h3>
<p>
Ordinary
JSON
documents
can
be
transformed
into
JSON-LD
documents
by
referencing
to
an
external
JSON-LD
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
in
an
HTTP
Link
Header.
Doing
this
allows
JSON
to
be
unambiguously
machine-readable
without
requiring
developers
to
drastically
change
their
workflow
and
provides
an
upgrade
path
for
existing
infrastructure
without
breaking
existing
clients
that
rely
on
the
<code>
application/json
</code>
media
type.
</p>
<p>
In
order
to
use
an
external
context
with
an
ordinary
JSON
document,
an
author
<em class="rfc2119" title="must">
must
</em>
specify
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
a
valid
JSON-LD
document
in
an
HTTP
Link
Header
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RFC5988">
RFC5988
</a>
</cite>
]
using
the
<code>
describedby
</code>
link
relation.
The
referenced
document
<em class="rfc2119" title="must">
must
</em>
have
a
top-level
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>.
The
<code>
@context
</code>
subtree
within
that
object
is
added
to
the
top-level
<del class="diff-old">object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins></a>
of
the
referencing
document.
If
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
is
at
the
top-level
of
the
referencing
document
and
its
items
are
<del class="diff-old">objects,
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definitions
</ins></a>,
the
<code>
@context
</code>
subtree
is
added
to
all
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
items.
All
extra
information
located
outside
of
the
<code>
@context
</code>
subtree
in
the
referenced
document
<em class="rfc2119" title="must">
must
</em>
be
discarded.
</p>
<p>
The
following
example
demonstrates
the
use
of
an
external
context
with
an
ordinary
JSON
document:
</p>
<del class="diff-old">GET /ordinary-json-document.json HTTP/1.1
</del>
<div class="example"><div class="example-title"><span>Example 25</span></div><pre class="example">GET /ordinary-json-document.json HTTP/1.1
Host: example.com
Accept: application/ld+json,application/json,*/*;q=0.1
====================================
HTTP/1.0 200 OK
...
Content-Type: <span class="diff">application/json</span>
<span class="diff">Link: &lt;http://json-ld.org/contexts/person.jsonld&gt;; rel=&quot;describedby&quot;; type=&quot;application/ld+json&quot;</span>
{
  &quot;name&quot;: &quot;Markus Lanthaler&quot;,
  &quot;homepage&quot;: &quot;http://www.markus-lanthaler.com/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/markuslanthaler&quot;
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
JSON-LD
documents
served
with
the
<code>
application/ld+json
</code>
media
type
<em class="rfc2119" title="must">
must
</em>
have
all
context
information,
including
references
to
external
contexts,
within
the
body
of
the
document.
</p>
</div>
</div>
<div id="expanded-term-definition" class="section">
<h3>
<span class="secno">
4.5
</span>
Expanded
Term
Definition
</h3>
<p>
Within
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definition,
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
<em class="rfc2119" title="may">
may
</em>
be
defined
using
an
expanded
notation
to
allow
for
additional
information
associated
with
the
term
to
be
specified
(see
also
<a href="#type-coercion">
Type
Coercion
</a>
and
<a href="#sets-and-lists">
Sets
and
Lists
</a>
).
</p>
<p>
Instead
of
using
a
string
representation
of
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>,
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<em class="rfc2119" title="may">
may
</em>
be
specified
using
<del class="diff-old">an
</del>
<ins class="diff-chg">a
</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
JSON
</ins>
object
</a>
having
an
<code>
@id
</code>
key.
The
value
of
the
<code>
@id
</code>
key
<em class="rfc2119" title="must">
must
</em>
be
either
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
<ins class="diff-new">Such
an
object
is
called
a
</ins><a class="tref internalDFN" title="subject_reference" href="#dfn-subject_reference"><ins class="diff-new">
subject
reference
</ins></a>.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 26</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: <span class="diff">{ &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/&quot; }</span>,
    &quot;name&quot;: <span class="diff">{ &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot; }</span>,
    &quot;homepage&quot;: <span class="diff">{ &quot;@id&quot;: &quot;foaf:homepage&quot; }</span>,
    &quot;depiction&quot;: <span class="diff">{ &quot;@id&quot;: &quot;foaf:depiction&quot; }</span>
  },
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
}
</pre>
</div>
<p>
This
allows
additional
information
to
be
associated
with
the
term.
This
<em class="rfc2119" title="may">
may
</em>
be
used
for
<a href="#type-coercion">
Type
Coercion
</a>,
<a href="#sets-and-lists">
Sets
and
Lists
</a>
),
or
to
associate
language
information
with
a
term
as
shown
in
the
following
example:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 27</span></div><pre class="example">{
  &quot;@context&quot;: {
    ...
    &quot;ex&quot;: &quot;http://example.com/&quot;,
    &quot;@language&quot;: &quot;ja&quot;,
    &quot;name&quot;: { &quot;@id&quot;: &quot;ex:name&quot;, <span class="diff">&quot;@language&quot;: null</span> },
    &quot;occupation&quot;: { &quot;@id&quot;: &quot;ex:occupation&quot; },
    &quot;occupation_en&quot;: { &quot;@id&quot;: &quot;ex:occupation&quot;, <span class="diff">&quot;@language&quot;: &quot;en&quot;</span> },
    &quot;occupation_cs&quot;: { &quot;@id&quot;: &quot;ex:occupation&quot;, <span class="diff">&quot;@language&quot;: &quot;cs&quot;</span> }
  },
  <span class="diff">&quot;name&quot;: &quot;Yagyū Muneyoshi&quot;,
  &quot;occupation&quot;: &quot;忍者&quot;,
  &quot;occupation_en&quot;: &quot;Ninja&quot;,
  &quot;occupation_cs&quot;: &quot;Nindža&quot;,</span>
  ...
}
</pre>
</div>
<p>
The
example
above
would
associate
<em>
忍者
</em>
with
the
specified
default
language
code
<code>
ja
</code>,
<em>
Ninja
</em>
with
the
language
code
<code>
en
</code>,
and
<em>
Nindža
</em>
with
the
language
code
<code>
cs
</code>.
The
value
of
<code>
name
</code>,
<em>
Yagyū
Muneyoshi
</em>
wouldn't
be
associated
with
any
language
code
since
<code>
@language
</code>
was
reset
to
<a class="tref internalDFN" title="null" href="#dfn-null">
null
</a>
in
the
expanded
term
definition.
</p>
<p>
Expanded
terms
<em class="rfc2119" title="may">
may
</em>
also
be
defined
using
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
IRIs
</a>
or
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
IRIs
</a>
as
keys.
If
the
definition
does
not
include
an
<code>
@id
</code>
key,
the
expanded
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
determined
by
performing
expansion
of
the
key
within
the
current
active
context.
This
mechanism
is
mainly
used
to
associate
type
or
language
information
with
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
an
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
While
it
is
possible
to
define
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
an
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
to
expand
to
some
other
unrelated
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
(for
example,
<code>
foaf:name
</code>
expanding
to
<code>
http://example.org/unrelated#species
</code>
),
such
usage
is
strongly
discouraged.
</p>
</div>
</div>
<div id="type-coercion" class="section">
<h3>
<span class="secno">
4.6
</span>
Type
Coercion
</h3>
<p>
JSON-LD
supports
the
coercion
of
values
to
particular
data
types.
Type
<dfn title="coercion" id="dfn-coercion">
coercion
</dfn>
allows
someone
deploying
JSON-LD
to
coerce
the
incoming
or
outgoing
values
to
the
proper
data
type
based
on
a
mapping
of
data
type
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
to
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s.
Using
type
coercion,
value
representation
is
preserved
without
requiring
the
data
type
to
be
specified
with
each
piece
of
data.
</p>
<p>
Type
coercion
is
specified
within
an
<a href="#expanded-term-definition">
expanded
term
definition
</a>
using
the
<code>
@type
</code>
key.
The
value
of
this
key
represents
a
type
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
and
<em class="rfc2119" title="must">
must
</em>
take
the
form
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
the
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
<code>
@id
</code>.
Specifying
<code>
@id
</code>
indicates
that
within
the
body
of
a
JSON-LD
document,
a
string
value
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
coerced
to
<code>
@id
</code>
is
to
be
interpreted
as
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<p>
<a class="tref internalDFN" title="term" href="#dfn-term">
Terms
</a>
or
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
IRIs
</a>
used
as
the
value
of
a
<code>
@type
</code>
key
<em class="rfc2119" title="may">
may
</em>
be
defined
within
the
same
context.
This
means
that
one
may
specify
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
like
<code>
xsd
</code>
and
then
use
<code>
xsd:integer
</code>
within
the
same
context
definition
-
the
JSON-LD
processor
will
be
able
to
determine
the
proper
expansion
for
<code>
xsd:integer
</code>.
</p>
<p>
The
example
below
demonstrates
how
a
JSON-LD
author
can
coerce
values
to
<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
typed
value
</a>
s,
IRIs
and
lists.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 28</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;age&quot;:
    <span class="diff">{
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/age&quot;,
      &quot;@type&quot;: &quot;xsd:integer&quot;
    }</span>,
    &quot;homepage&quot;:
    <span class="diff">{
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;,
      &quot;@container&quot;: &quot;@list&quot;
    }</span>
  },
  &quot;name&quot;: &quot;John Smith&quot;,
  &quot;age&quot;: <span class="diff">&quot;41&quot;</span>,
  &quot;homepage&quot;:
  <span class="diff">[
    &quot;http://personal.example.org/&quot;,
    &quot;http://work.example.com/jsmith/&quot;
  ]</span>
}
</pre>
</div>
<p>
The
example
above
would
generate
the
following
Turtle:
</p>
<del class="diff-old">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .
</del>
<div class="example"><div class="example-title"><span>Example 29</span></div><pre class="example">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .
[ foaf:name &quot;John Smith&quot;;
  foaf:age  &quot;41&quot;^^xsd:integer;
  foaf:homepage ( &lt;http://personal.example.org/&gt; &lt;http://work.example.com/jsmith/&gt; )
]
.
</pre>
</div>
<p>
Terms
may
also
be
defined
using
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
IRIs
</a>
or
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
IRIs
</a>.
This
allows
coercion
rules
to
<del class="diff-old">by
</del>
<ins class="diff-chg">be
</ins>
applied
to
keys
which
are
not
represented
as
a
simple
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>.
For
example:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 30</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;</span>,
    &quot;<span class="diff">foaf:age</span>&quot;:
    {
      &quot;@type&quot;: &quot;xsd:integer&quot;
    },
    &quot;<span class="diff">foaf:homepage</span>&quot;:
    <span class="diff">{
      &quot;@type&quot;: &quot;@id&quot;
    }</span>
  },
  &quot;foaf:name&quot;: &quot;John Smith&quot;,
  &quot;foaf:age&quot;: <span class="diff">&quot;41&quot;</span>,
  &quot;foaf:homepage&quot;:
  <span class="diff">[
    &quot;http://personal.example.org/&quot;,
    &quot;http://work.example.com/jsmith/&quot;
  ]</span>
}
</pre>
</div>
<p>
In
this
case
the
<code>
@id
</code>
definition
is
optional,
but
if
it
does
exist,
the
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
is
treated
as
a
term
(not
a
<code>
prefix:suffix
</code>
construct)
so
that
the
actual
definition
of
a
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
becomes
unnecessary.
</p>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-chg">Note
</ins></span></div><p class="">
Keys
in
the
context
are
treated
as
<a class="tref internalDFN" title="term" href="#dfn-term">
terms
</a>
for
the
purpose
of
expansion
and
value
coercion.
At
times,
this
may
result
in
multiple
representations
for
the
same
expanded
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>.
For
example,
one
could
specify
that
<code>
dog
</code>
and
<code>
cat
</code>
both
expanded
to
<code>
http://example.com/vocab#animal
</code>.
Doing
this
could
be
useful
for
establishing
different
type
coercion
or
language
specification
rules.
It
also
allows
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
(or
even
an
absolute
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
)
to
be
defined
as
something
else
entirely.
For
example,
one
could
specify
that
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
<code>
http://example.org/zoo
</code>
should
expand
to
<code>
http://example.org/river
</code>,
but
this
usage
is
discouraged
because
it
would
lead
to
a
great
deal
of
confusion
among
developers
attempting
to
understand
the
JSON-LD
document.
</p>
</div>
<p>
Type
coercion
is
performed
using
the
unexpanded
value
of
the
key,
which
<em class="rfc2119" title="must">
must
</em>
have
an
exact
match
for
an
entry
in
the
<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
active
context
</a>.
</p>
</div>
<div id="iri-expansion-within-a-context" class="section">
<h3>
<span class="secno">
4.7
</span>
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
Expansion
Within
a
Context
</h3>
<p>
In
general,
normal
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
expansion
rules
apply
anywhere
an
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
is
expected
(see
<a href="#iris">
IRIs
</a>
).
Within
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definition,
this
can
mean
that
terms
defined
within
the
context
<em class="rfc2119" title="may">
may
</em>
also
be
used
within
that
context
as
long
as
there
are
no
circular
dependencies.
For
example,
it
is
common
to
use
the
<code>
xsd
</code>
namespace
when
defining
<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
typed
value
</a>
s:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 31</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;</span>,
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;age&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/age&quot;,
      &quot;@type&quot;: <span class="diff">&quot;xsd:integer&quot;</span>
    },
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
  },
  ...
}
</pre>
</div>
<p>
In
this
example,
the
<code>
xsd
</code>
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
is
defined
and
used
as
a
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
for
the
<code>
@type
</code>
coercion
of
the
<code>
age
</code>
property.
</p>
<p>
<a class="tref internalDFN" title="term" href="#dfn-term">
Term
</a>
s
<em class="rfc2119" title="may">
may
</em>
also
be
used
when
defining
the
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
of
another
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 32</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;</span>,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: <span class="diff">&quot;foaf:name&quot;</span>,
    &quot;age&quot;:
    {
      &quot;@id&quot;: <span class="diff">&quot;foaf:age&quot;</span>,
      &quot;@type&quot;: &quot;xsd:integer&quot;
    },
    &quot;homepage&quot;:
    {
      &quot;@id&quot;: <span class="diff">&quot;foaf:homepage&quot;</span>,
      &quot;@type&quot;: &quot;@id&quot;
    }
  },
  ...
}
</pre>
</div>
<p>
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
Compact
IRIs
</a>
and
<a class="tref internalDFN" title="iri" href="#dfn-iri">
IRIs
</a>
<em class="rfc2119" title="may">
may
</em>
be
used
on
the
left-hand
side
of
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
definition.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 33</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;</span>,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: &quot;foaf:name&quot;,
    &quot;<span class="diff">foaf:age</span>&quot;:
    {
      &quot;@type&quot;: &quot;xsd:integer&quot;
    },
    &quot;<span class="diff">foaf:homepage</span>&quot;:
    <span class="diff">{
      &quot;@type&quot;: &quot;@id&quot;
    }</span>
  },
  ...
}
</pre>
</div>
<p>
In
this
example,
the
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
form
is
used
in
two
different
ways.
In
the
first
approach,
<code>
foaf:age
</code>
declares
both
the
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
the
term
(using
short-form)
as
well
as
the
<code>
@type
</code>
associated
with
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>.
In
the
second
approach,
only
the
<code>
@type
</code>
associated
with
the
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
is
specified.
The
JSON-LD
processor
will
derive
the
full
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
for
<code>
foaf:homepage
</code>
by
looking
up
the
<code>
foaf
</code>
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
in
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>.
</p>
<p>
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
Absolute
IRIs
</a>
<em class="rfc2119" title="may">
may
</em>
also
be
used
in
the
key
position
in
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 34</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
    &quot;name&quot;: &quot;foaf:name&quot;,
    &quot;foaf:age&quot;:
    {
      &quot;@id&quot;: &quot;foaf:age&quot;,
      &quot;@type&quot;: &quot;xsd:integer&quot;
    },
    &quot;<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>&quot;:
    {
      &quot;@type&quot;: &quot;@id&quot;
    }
  },
  ...
}
</pre>
</div>
<p>
In
order
for
the
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
to
match
above,
the
<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
absolute
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<em class="rfc2119" title="must">
must
</em>
also
be
used
in
the
JSON-LD
document.
Also
note
that
<code>
foaf:homepage
</code>
will
not
use
the
<code>
{
&quot;@type&quot;:
&quot;@id&quot;
}
</code>
declaration
because
<code>
foaf:homepage
</code>
is
not
the
same
as
<code>
http://xmlns.com/foaf/0.1/homepage
</code>.
That
is,
a
JSON-LD
processor
will
use
direct
string
comparison
when
looking
up
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>
s
in
a
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
before
it
applies
the
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>
lookup
mechanism.
</p>
<p>
The
only
exception
for
using
terms
in
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
is
that
they
<em class="rfc2119" title="must not">
must
not
</em>
be
used
in
a
circular
manner.
That
is,
a
definition
of
<em>
term-1
</em>
<em class="rfc2119" title="must not">
must
not
</em>
depend
on
the
definition
of
<em>
term-2
</em>
if
<em>
term-2
</em>
also
depends
on
<em>
term-1
</em>.
For
example,
the
following
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
definition
is
illegal:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 35</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;term1&quot;: &quot;term2:foo&quot;,
    &quot;term2&quot;: &quot;term1:bar&quot;</span>
  },
  ...
}
</pre>
</div>
</div>
<div id="sets-and-lists" class="section">
<h3>
<span class="secno">
4.8
</span>
<ins class="diff-new">Sets
and
Lists
</ins></h3><p><ins class="diff-new">
A
JSON-LD
author
can
express
multiple
values
in
a
compact
way
by
using
</ins><a class="tref internalDFN" title="array" href="#dfn-array"><ins class="diff-new">
array
</ins></a><ins class="diff-new">
s.
Since
graphs
do
not
describe
ordering
for
links
between
nodes,
arrays
in
JSON-LD
do
not
provide
an
ordering
of
the
listed
</ins><a class="tref internalDFN" title="object" href="#dfn-object"><ins class="diff-new">
objects
</ins></a><ins class="diff-new">
by
default.
This
is
exactly
the
opposite
from
regular
JSON
arrays,
which
are
ordered
by
default.
For
example,
consider
the
following
simple
document:
</ins></p><div class="example"><div class="example-title"><span>Example 36</span></div><pre class="example">{<ins class="diff-new">
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: <span class="diff">[ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]</span>,
...
}
</ins></pre></div><p><ins class="diff-new">
The
markup
shown
above
would
result
in
three
triples
being
generated,
each
relating
the
subject
to
an
individual
</ins><a class="tref internalDFN" title="object" href="#dfn-object"><ins class="diff-new">
object
</ins></a>,<ins class="diff-new">
with
no
inherent
order:
</ins></p><div class="example"><div class="example-title"><span>Example 37</span></div><pre class="example">&lt;http://example.org/people#joebob&gt;<ins class="diff-new">
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;joe&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
      &quot;bob&quot; .
&lt;http://example.org/people#joebob&gt;
   &lt;http://xmlns.com/foaf/0.1/nick&gt;
&quot;jaybee&quot;
.
</ins></pre></div><p><ins class="diff-new">
Multiple
values
may
also
be
expressed
using
the
expanded
form:
</ins></p><div class="example"><div class="example-title"><span>Example 38</span></div><pre class="example">{<ins class="diff-new">
  &quot;@id&quot;: &quot;http://example.org/articles/8&quot;,
  &quot;dc:title&quot;: <span class="diff">
  [
    {
      &quot;@value&quot;: &quot;Das Kapital&quot;,
      &quot;@language&quot;: &quot;de&quot;
    },
    {
      &quot;@value&quot;: &quot;Capital&quot;,
      &quot;@language&quot;: &quot;en&quot;
    }
  ]</span>
}
</ins></pre></div><p><ins class="diff-new">
The
markup
shown
above
would
generate
the
following
triples,
again
with
no
inherent
order:
</ins></p><div class="example"><div class="example-title"><span>Example 39</span></div><pre class="example">&lt;http://example.org/articles/8&gt;<ins class="diff-new">
   &lt;http://purl.org/dc/terms/title&gt;
      &quot;Das Kapital&quot;@de .
&lt;http://example.org/articles/8&gt;
   &lt;http://purl.org/dc/terms/title&gt;
&quot;Capital&quot;@en
.
</ins></pre></div><p><ins class="diff-new">
As
the
notion
of
ordered
collections
is
rather
important
in
data
modeling,
it
is
useful
to
have
specific
language
support.
In
JSON-LD,
a
list
may
be
represented
using
the
</ins><code><ins class="diff-new">
@list
</ins></code><a class="tref internalDFN" title="keyword" href="#dfn-keyword"><ins class="diff-new">
keyword
</ins></a><ins class="diff-new">
as
follows:
</ins></p><div class="example"><div class="example-title"><span>Example 40</span></div><pre class="example">{<ins class="diff-new">
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;foaf:nick&quot;:
</ins>  <span class="diff">{<ins class="diff-new">
    &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]
  }</span>,
...
}
</ins></pre></div><p><ins class="diff-new">
This
describes
the
use
of
this
</ins><a class="tref internalDFN" title="array" href="#dfn-array"><ins class="diff-new">
array
</ins></a><ins class="diff-new">
as
being
ordered,
and
order
is
maintained
when
processing
a
document.
If
every
use
of
a
given
multi-valued
property
is
a
list,
this
may
be
abbreviated
by
setting
</ins><code><ins class="diff-new">
@container
</ins></code><ins class="diff-new">
to
</ins><code><ins class="diff-new">
@list
</ins></code><ins class="diff-new">
in
the
</ins><a class="tref internalDFN" title="context" href="#dfn-context"><ins class="diff-new">
context
</ins></a>:</p><div class="example"><div class="example-title"><span>Example 41</span></div><pre class="example">{  <span class="diff">&quot;@context&quot;:<ins class="diff-new">
  {
    ...
    &quot;nick&quot;:
    {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/nick&quot;,
      &quot;@container&quot;: &quot;@list&quot;
    }
  }</span>,
...
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;nick&quot;: <span class="diff">[ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]</span>,
...
}
</ins></pre></div><div class="note"><div class="note-title"><span><ins class="diff-new">
Note
</ins></span></div><p class=""><ins class="diff-new">
List
of
lists
are
not
allowed
in
this
version
of
JSON-LD.
If
a
list
of
lists
is
detected,
a
JSON-LD
processor
will
throw
an
exception.
This
decision
was
made
due
to
the
extreme
amount
of
added
complexity
when
processing
lists
of
lists.
</ins></p></div><p><ins class="diff-new">
Similarly
to
</ins><code><ins class="diff-new">
@list
</ins></code>,<ins class="diff-new">
there
exists
the
</ins><a class="tref internalDFN" title="keyword" href="#dfn-keyword"><ins class="diff-new">
keyword
</ins></a><code><ins class="diff-new">
@set
</ins></code><ins class="diff-new">
to
describe
unordered
sets.
While
its
use
in
the
body
of
a
JSON-LD
document
represents
just
syntactic
sugar
that
</ins><em class="rfc2119" title="must"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
be
optimized
away
when
processing
the
document,
it
is
very
helpful
when
used
within
the
context
of
a
document.
Values
of
terms
associated
with
a
</ins><code><ins class="diff-new">
@set
</ins></code><ins class="diff-new">
or
</ins><code><ins class="diff-new">
@list
</ins></code><ins class="diff-new">
container
are
always
represented
in
the
form
of
an
</ins><a class="tref internalDFN" title="array" href="#dfn-array"><ins class="diff-new">
array
</ins></a><ins class="diff-new">
-
even
if
there
is
just
a
single
value
that
would
otherwise
be
optimized
to
a
non-array
form
in
a
</ins><a href="#compact-document-form"><ins class="diff-new">
compacted
document
</ins></a>.<ins class="diff-new">
This
makes
post-processing
of
the
data
easier
as
the
data
is
always
in
array
form,
even
if
the
array
only
contains
a
single
value.
</ins></p><div class="note"><div class="note-title"><span><ins class="diff-new">
Note
</ins></span></div><p class=""><ins class="diff-new">
The
use
of
</ins><code><ins class="diff-new">
@container
</ins></code><ins class="diff-new">
in
the
body
of
a
JSON-LD
document,
i.e.,
outside
</ins><code><ins class="diff-new">
@context
</ins></code><em class="rfc2119" title="must"><ins class="diff-new">
must
</ins></em><ins class="diff-new">
be
ignored
by
JSON-LD
processors.
</ins></p></div></div><div id="embedding" class="section"><h3><span class="secno"><ins class="diff-new">
4.9
</ins></span>
Embedding
</h3>
<p>
Object
<dfn title="embedding" id="dfn-embedding">
embedding
</dfn>
is
a
JSON-LD
feature
that
allows
an
author
to
use
<del class="diff-old">the
definition
of
JSON-LD
objects
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definitions
</ins></a>
as
<a class="tref internalDFN" title="property" href="#dfn-property">
property
</a>
values.
This
is
a
commonly
used
mechanism
for
creating
a
parent-child
relationship
between
two
<a class="tref internalDFN" title="subject" href="#dfn-subject">
subject
</a>
s.
</p>
<p>
The
example
shows
two
subjects
related
by
a
property
from
the
first
subject:
</p>
<del class="diff-old">  {
</del>
  <div class="example"><div class="example-title"><span>Example 42</span></div><pre class="example">{
...
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;<span class="diff">knows</span>&quot;:
  {
    &quot;<span class="diff">@type</span>&quot;: &quot;<span class="diff">Person</span>&quot;,
    &quot;<span class="diff">name</span>&quot;: &quot;<span class="diff">Gregg Kellogg</span>&quot;,
  }
...
}
</pre>
</div>
<p>
<del class="diff-old">An
object
definition,
</del>
<ins class="diff-chg">A
</ins><a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition"><ins class="diff-chg">
subject
definition
</ins></a>,
like
the
one
used
above,
<em class="rfc2119" title="may">
may
</em>
be
used
in
any
value
position
in
the
body
of
a
JSON-LD
document.
</p>
</div>
<div id="named-graphs" class="section">
<h3>
<span class="secno">
<del class="diff-old">4.9
</del>
<ins class="diff-chg">4.10
</ins>
</span>
Named
Graphs
</h3>
<p>
The
<code>
@graph
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
is
used
to
express
a
set
of
JSON-LD
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
subject
definition
</a>
s
that
may
not
be
directly
related
to
one
another
through
a
property.
The
mechanism
may
also
be
used
where
<a class="tref internalDFN" title="embedding" href="#dfn-embedding">
embedding
</a>
is
not
desirable
to
the
application.
For
example:
</p>
<del class="diff-old">  {
</del>
  <div class="example"><div class="example-title"><span>Example 43</span></div><pre class="example">{
  &quot;@context&quot;: ...,
  &quot;<span class="diff">@graph</span>&quot;:
  [
    {
      &quot;@id&quot;: &quot;http://manu.sporny.org/i/public&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;name&quot;: &quot;Manu Sporny&quot;,
      &quot;knows&quot;: &quot;http://greggkellogg.net/foaf#me&quot;
    },
    {
      &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;name&quot;: &quot;Gregg Kellogg&quot;,
      &quot;knows&quot;: &quot;http://manu.sporny.org/i/public&quot;
    }
  ]
}
</pre>
</div>
<p>
In
this
case,
embedding
doesn't
work
as
each
<del class="diff-old">JSON-LD
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins></a>
references
the
other.
Using
the
<code>
@graph
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
allows
multiple
resources
to
be
defined
within
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>,
and
allows
the
use
of
a
shared
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>.
<ins class="diff-new">When
used
in
a
</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-new">
JSON
object
</ins></a><ins class="diff-new">
that
is
not
otherwise
a
</ins><a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition"><ins class="diff-new">
subject
definition
</ins></a>,<ins class="diff-new">
this
describes
resources
in
the
</ins><em><ins class="diff-new">
default
graph
</ins></em>.
This
is
equivalent
to
using
multiple
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
</ins>
definitions
</a>
in
array
and
defining
the
<code>
@context
</code>
within
each
<del class="diff-old">object:
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins></a>:
</p>
<del class="diff-old">  
</del>
  <div class="example"><div class="example-title"><span>Example 44</span></div><pre class="example"><span class="diff">[</span>
  {
    <span class="diff">&quot;@context&quot;: ...,</span>
    &quot;@id&quot;: &quot;http://manu.sporny.org/i/public&quot;,
    &quot;@type&quot;: &quot;foaf:Person&quot;,
    &quot;name&quot;: &quot;Manu Sporny&quot;,
    &quot;knows&quot;: &quot;http://greggkellogg.net/foaf#me&quot;
  },
  {
    <span class="diff">&quot;@context&quot;: ...,</span>
    &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
    &quot;@type&quot;: &quot;foaf:Person&quot;,
    &quot;name&quot;: &quot;Gregg Kellogg&quot;,
    &quot;knows&quot;: &quot;http://manu.sporny.org/i/public&quot;
  }
<span class="diff">
]
</span>
</pre>
</div>
<p>
JSON-LD
allows
you
to
<em>
name
</em>
things
on
the
Web
by
assigning
an
<code>
@id
</code>
to
them,
which
is
typically
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
This
notion
extends
to
the
ability
to
identify
graphs
in
the
same
manner.
A
developer
may
name
data
expressed
using
the
<code>
@graph
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>
by
pairing
it
with
an
<code>
@id
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
This
enables
the
developer
to
make
statements
about
<del class="diff-old">the
</del>
<ins class="diff-chg">a
</ins>
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
itself,
rather
than
just
a
single
<del class="diff-old">JSON-LD
object.
</del>
<a class="tref internalDFN" title="subject" href="#dfn-subject">
<ins class="diff-chg">subject
</ins></a>.
</p>
<del class="diff-old">  {
</del>
  <div class="example"><div class="example-title"><span>Example 45</span></div><pre class="example">{
  &quot;@context&quot;: ...,
  <span class="diff">&quot;@id&quot;: &quot;http://example.org/graphs/73&quot;,
  &quot;asOf&quot;: { &quot;@value&quot;: &quot;2012-04-09&quot;, &quot;@type&quot;: &quot;xsd:date&quot; },
  &quot;@graph&quot;:</span>
  [
    {
      &quot;@id&quot;: &quot;http://manu.sporny.org/i/public&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;name&quot;: &quot;Manu Sporny&quot;,
      &quot;knows&quot;: &quot;http://greggkellogg.net/foaf#me&quot;
    },
    {
      &quot;@id&quot;: &quot;http://greggkellogg.net/foaf#me&quot;,
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;name&quot;: &quot;Gregg Kellogg&quot;,
      &quot;knows&quot;: &quot;http://manu.sporny.org/i/public&quot;
<del class="diff-old">    },
    &quot;http://www.markus-lanthaler.com/&quot;
</del>
<ins class="diff-chg">    }
</ins>
  ]
}
</pre>
</div>
<p>
The
example
above
expresses
a
<em>
named
</em>
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
that
is
identified
by
the
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
<code>
http://example.org/graphs/73
</code>.
That
graph
is
composed
of
the
statements
about
Manu
and
<del class="diff-old">Gregg
and
a
reference
to
another
IRI
,
which
could
make
statements
about
Markus.
</del>
<ins class="diff-chg">Gregg.
</ins>
Meta-data
about
the
graph
itself
is
also
expressed
via
the
<code>
asOf
</code>
property,
which
specifies
when
the
information
was
retrieved
from
the
Web.
</p>
<div class="issue">
<div class="issue-title">
<span>
<ins class="diff-new">Issue
3
</ins></span>
</div>
<p class="">
<ins class="diff-chg">These
examples
could
all
have
TriG
definitions
of
their
RDF
results,
but
that
would
involve
adding
RDF
earlier
in
the
document.
</ins></p></div></div><div id="identifying-unlabeled-nodes" class="section">
<h3>
<span class="secno">
<del class="diff-old">4.10
</del>
<ins class="diff-chg">4.11
</ins>
</span>
Identifying
Unlabeled
Nodes
</h3>
<p>
At
times,
it
becomes
necessary
to
be
able
to
express
information
without
being
able
to
specify
the
subject.
Typically,
this
type
of
node
is
called
an
<dfn title="unlabeled_node" id="dfn-unlabeled_node">
unlabeled
node
</dfn>
or
a
blank
<del class="diff-old">node.
</del>
<ins class="diff-chg">node
(see
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS"><ins class="diff-chg">
RDF-CONCEPTS
</ins></a></cite><ins class="diff-chg">
]
</ins><cite><a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes"><ins class="diff-chg">
Section
3.4:
Blank
Nodes
</ins></a></cite><ins class="diff-chg">
).
</ins>
In
JSON-LD,
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
</a>
identifiers
are
automatically
created
if
a
subject
is
not
specified
using
the
<code>
@id
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keyword
</a>.
However,
authors
may
provide
identifiers
for
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
nodes
</a>
by
using
the
special
<code>
_
</code>
(underscore)
<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
prefix
</a>.
This
allows
one
to
reference
the
node
locally
within
the
document,
but
makes
it
impossible
to
reference
the
node
from
an
external
document.
The
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
</a>
identifier
is
scoped
to
the
document
in
which
it
is
used.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 46</span></div><pre class="example">{
...
  &quot;@id&quot;: &quot;<span class="diff">_:foo</span>&quot;,
...
}
</pre>
</div>
<p>
The
example
above
would
set
the
subject
to
<code>
_:foo
</code>,
which
can
then
be
used
elsewhere
in
the
JSON-LD
document
to
refer
back
to
the
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
</a>.
<del class="diff-old">This
practice
is
frowned
upon
when
generating
Linked
Data
.
</del>
If
a
developer
finds
that
they
refer
to
the
unlabeled
node
more
than
once,
they
should
consider
naming
the
node
using
a
de-referenceable
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
<del class="diff-old">.
</del>
</a>
<ins class="diff-chg">so
that
it
can
be
referenced
also
from
other
documents.
</ins>
</p>
</div>
<div id="aliasing-keywords" class="section">
<h3>
<span class="secno">
<del class="diff-old">4.11
</del>
<ins class="diff-chg">4.12
</ins>
</span>
Aliasing
Keywords
</h3>
<p>
Each
of
the
JSON-LD
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keywords
</a>,
except
for
<code>
@context
</code>,
<em class="rfc2119" title="may">
may
</em>
be
aliased
to
application-specific
keywords.
This
feature
allows
legacy
JSON
content
to
be
utilized
by
JSON-LD
by
re-using
JSON
keys
that
already
exist
in
legacy
documents.
This
feature
also
allows
developers
to
design
domain-specific
implementations
using
only
the
JSON-LD
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 47</span></div><pre class="example">{
  &quot;@context&quot;:
  {
     <span class="diff">&quot;url&quot;: &quot;@id&quot;</span>,
     <span class="diff">&quot;a&quot;: &quot;@type&quot;</span>,
     &quot;name&quot;: &quot;http://schema.org/name&quot;
  },
  &quot;<span class="diff">url</span>&quot;: &quot;http://example.com/about#gregg&quot;,
  &quot;<span class="diff">a</span>&quot;: &quot;http://schema.org/Person&quot;,
  &quot;name&quot;: &quot;Gregg Kellogg&quot;
}
</pre>
</div>
<p>
In
the
example
above,
the
<code>
@id
</code>
and
<code>
@type
</code>
<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
keywords
</a>
have
been
given
the
aliases
<strong>
url
</strong>
and
<strong>
a
</strong>,
respectively.
</p>
</div>
<div id="expanded-document-form" class="section">
<h3>
<span class="secno">
<del class="diff-old">4.12
</del>
<ins class="diff-chg">4.13
</ins>
</span>
Expanded
Document
Form
</h3>
<p>
The
JSON-LD
API
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
JSON-LD-API
</a>
</cite>
]
defines
an
method
for
<em>
expanding
</em>
a
JSON-LD
document.
Expansion
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
<code>
@context
</code>
such
that
all
IRIs,
<del class="diff-old">datatypes,
</del>
<ins class="diff-chg">types,
</ins>
and
values
are
expanded
so
that
the
<code>
@context
</code>
is
no
longer
necessary.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 48</span></div><pre class="example">{
   &quot;@context&quot;:
   {
      &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
      &quot;homepage&quot;: {
        &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
        &quot;@type&quot;, &quot;@id&quot;
      }
   },
   &quot;name&quot;: &quot;Manu Sporny&quot;,
   &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
Running
the
JSON-LD
Expansion
algorithm
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<del class="diff-old">[
</del>
<div class="example"><div class="example-title"><span>Example 49</span></div><pre class="example">[
  {
    &quot;http://xmlns.com/foaf/0.1/name&quot;: [
      { &quot;@value&quot;: &quot;Manu Sporny&quot; }
    ],
    &quot;http://xmlns.com/foaf/0.1/homepage&quot;: [
      { &quot;@id&quot;: &quot;http://manu.sporny.org/&quot; }
    ]
  }
]
</pre>
</div>
<p>
Expanded
document
form
is
useful
when
an
application
has
to
process
input
data
in
a
deterministic
form.
It
has
been
optimized
to
ensure
that
the
code
that
developers
have
to
write
is
minimized
compared
to
the
code
that
would
have
to
be
written
to
operate
on
<a href="#compact-document-form">
compact
document
form
</a>.
</p>
</div>
<div id="compact-document-form" class="section">
<h3>
<span class="secno">
<del class="diff-old">4.13
</del>
<ins class="diff-chg">4.14
</ins>
</span>
Compact
Document
Form
</h3>
<p>
The
JSON-LD
API
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
JSON-LD-API
</a>
</cite>
]
defines
a
method
for
<em>
compacting
</em>
a
JSON-LD
document.
Compaction
is
the
process
of
taking
a
JSON-LD
document
and
applying
a
context
such
that
the
most
compact
form
of
the
document
is
generated.
JSON
is
typically
expressed
in
a
very
compact,
key-value
format.
That
is,
full
IRIs
are
rarely
used
as
keys.
At
times,
a
JSON-LD
document
may
be
received
that
is
not
in
its
most
compact
form.
JSON-LD,
via
the
API,
provides
a
way
to
compact
a
JSON-LD
document.
</p>
<p>
For
example,
assume
the
following
JSON-LD
input
document:
</p>
<del class="diff-old">[
</del>
<div class="example"><div class="example-title"><span>Example 50</span></div><pre class="example">[
  {
    &quot;http://xmlns.com/foaf/0.1/name&quot;: [ &quot;Manu Sporny&quot; ],
    &quot;http://xmlns.com/foaf/0.1/homepage&quot;: [
      {
       &quot;@id&quot;: &quot;http://manu.sporny.org/&quot;
      }
    ]
  }
]
</pre>
</div>
<p>
Additionally,
assume
the
following
developer-supplied
JSON-LD
context:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 51</span></div><pre class="example">{
  &quot;@context&quot;: {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;homepage&quot;: {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
  }
}
</pre>
</div>
<p>
Running
the
JSON-LD
Compaction
algorithm
given
the
context
supplied
above
against
the
JSON-LD
input
document
provided
above
would
result
in
the
following
output:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 52</span></div><pre class="example">{
  &quot;@context&quot;: {
    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
    &quot;homepage&quot;: {
      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    }
  },
  &quot;name&quot;: &quot;Manu Sporny&quot;,
  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;
}
</pre>
</div>
<p>
The
compaction
algorithm
enables
a
developer
to
map
any
document
into
an
application-specific
compacted
form
by
first
<a href="#expanded-document-form">
expanding
the
document
</a>.
While
the
context
provided
above
mapped
<code>
http://xmlns.com/foaf/0.1/name
</code>
to
<strong>
name
</strong>,
it
could
have
also
mapped
it
to
any
arbitrary
string
provided
by
the
developer.
This
powerful
mechanism,
along
with
another
JSON-LD
API
technique
called
<em>
framing
</em>,
allows
the
developer
to
re-shape
the
incoming
JSON
data
into
a
format
that
is
optimized
for
their
application.
</p>
</div>
</div>
<div class="appendix normative section" id="json-ld-authoring-guidelines">
<h2>
<span class="secno">
A.
</span>
JSON-LD
<del class="diff-old">Grammar
</del>
<ins class="diff-chg">Authoring
Guidelines
</ins>
</h2>
<p>
Since
the
JSON-LD
syntax
is
a
subset
of
the
JSON
syntax,
it
follows
that
all
<del class="diff-old">well-formed
</del>
<ins class="diff-chg">valid
</ins>
JSON-LD
documents
are
<del class="diff-old">well-formed
</del>
<ins class="diff-chg">valid
</ins>
JSON
documents.
It
also
means
that
<del class="diff-old">a
non-well-formed
</del>
<ins class="diff-chg">an
invalid
</ins>
JSON
document
can
never
be
a
<del class="diff-old">well-formed
</del>
<ins class="diff-chg">valid
</ins>
JSON-LD
document.
Furthermore,
JSON-LD
places
a
number
of
restrictions
on
the
JSON
syntax
in
order
to
define
a
<ins class="diff-new">set
of
authoring
</ins>
<em>
<del class="diff-old">grammar
</del>
<ins class="diff-chg">guidelines
</ins>
</em>
that
<del class="diff-old">is
</del>
<ins class="diff-chg">are
</ins>
used
to
express
<del class="diff-old">valid
</del>
<em>
<ins class="diff-chg">well-formed
</ins></em>
JSON-LD
documents.
At
times,
even
if
<del class="diff-old">this
grammar
is
</del>
<ins class="diff-chg">these
guidelines
are
</ins>
violated,
a
JSON-LD
processor
will
do
its
best
to
recover
from
the
<del class="diff-old">error
</del>
<ins class="diff-chg">mistake
</ins>
and
<ins class="diff-new">will
</ins>
deterministically
transform
the
author's
markup
into
<del class="diff-old">valid
</del>
<ins class="diff-chg">well-formed
</ins>
JSON-LD.
</p>
<div class="issue">
<div class="issue-title">
<span>
<ins class="diff-chg">Issue
4
</ins></span></div><p class="">
The
final
<del class="diff-old">nuanced
</del>
details
of
the
<del class="diff-old">exact
grammar
</del>
<ins class="diff-chg">guidelines
</ins>
are
still
being
discussed
<del class="diff-old">(see
</del>
<ins class="diff-chg">(
</ins>
<a href="https://github.com/json-ld/json-ld.org/issues/114#issuecomment-5820544">
ISSUE-114
</a>
),
as
well
as
the
best
mechanism
to
express
these
restrictions.
EBNF
<del class="diff-old">seems
like
overkill
since
it's
a
subset
of
JSON.
EBNF
</del>
doesn't
quite
capture
<del class="diff-old">some
of
the
more
esoteric
restrictions
in
</del>
<ins class="diff-chg">what
these
guidelines
are
attempting
to
do
-
which
is
strongly
express
what
constitutes
a
well-formed
JSON-LD
document.
For
</ins>
the
<del class="diff-old">language.
</del>
<ins class="diff-chg">time
being,
a
simple
list
of
plain
English
guidelines
are
provided.
</ins>
</p>
</div>
<div class="issue">
<div class="issue-title">
<span>
<ins class="diff-new">Issue
5
</ins></span></div><p class=""><ins class="diff-new">
Per
</ins><a href="http://lists.w3.org/Archives/Public/public-rdf-wg/2012Jun/0111.html"><ins class="diff-new">
Andy
S's
comment
</ins></a>,<ins class="diff-new">
consider
making
this
a
normative
syntax
definition
along
with
EBNF.
</ins></p></div>
<ol>
<li>
A
JSON-LD
document
is
composed
of
a
single
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
or
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
<del class="diff-old">of
JSON
object
</del>
</a>
<del class="diff-old">s.
</del>
<ins class="diff-chg">of
</ins><a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition"><ins class="diff-chg">
subject
definitions
</ins></a>.
</li>
<li>
The
value
of
<code>
@id
</code>
<em class="rfc2119" title="must">
must
</em>
be
<del class="diff-old">null
,
</del>
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</li>
<li>
<del class="diff-old">A
</del>
<ins class="diff-chg">An
</ins>
<code>
@id
</code>
keyword
and
a
<code>
@language
</code>
keyword
<em class="rfc2119" title="must not">
must
not
</em>
exist
in
the
same
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
</li>
<li>
<del class="diff-old">A
</del>
<ins class="diff-chg">An
</ins>
<code>
@id
</code>
keyword
and
a
<code>
@container
</code>
keyword
<em class="rfc2119" title="must not">
must
not
</em>
exist
in
the
same
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
</li>
<li>
A
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
<em class="rfc2119" title="may">
may
</em>
contain
a
<code>
@context
</code>
property.
</li>
<li>
A
<code>
@context
</code>
value
<em class="rfc2119" title="must not">
must
not
</em>
contain
an
embedded
<code>
@context
</code>
definition.
</li>
<li>
The
value
associated
with
the
<code>
@context
</code>
keyword
<em class="rfc2119" title="must">
must
</em>
be
<ins class="diff-new">a
string
expanding
to
</ins>
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
null,
or
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
containing
a
combination
of
the
allowed
values.
</li>
<li>
The
value
associated
with
the
keys
used
in
a
<code>
@context
</code>
<em class="rfc2119" title="must">
must
</em>
be
a
<code>
null
</code>,
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
or
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>.
</li>
<li>
For
each
value
that
is
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
that
is
associated
with
a
key
in
a
<code>
@context
</code>:
<ol>
<li>
<code>
@id
</code>
and
<code>
@type
</code>
<em class="rfc2119" title="must">
must
</em>
be
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
or
<code>
null
</code>
</li>
<li>
<code>
@container
</code>
<em class="rfc2119" title="must">
must
</em>
be
associated
with
a
value
of
either
<code>
@set
</code>
or
<code>
@list
</code>.
</li>
<li>
<code>
@language
</code>
<em class="rfc2119" title="must">
must
</em>
be
a
string
expressed
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-BCP47">
BCP47
</a>
</cite>
]
or
<code>
null
</code>.
</li>
<li>
Any
other
property
<em class="rfc2119" title="must">
must
</em>
be
ignored
by
a
JSON-LD
processor
and
<em class="rfc2119" title="must">
must
</em>
be
preserved
in
compaction
and
framing.
</li>
</ol>
</li>
<li>
A
<del class="diff-old">JSON
object
</del>
<a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition">
<ins class="diff-chg">subject
definition
</ins>
</a>
<em class="rfc2119" title="may">
may
</em>
have
an
<code>
@graph
</code>
property.
</li>
<li>
The
value
of
a
<code>
@graph
</code>
property
<em class="rfc2119" title="must">
must
</em>
be
<del class="diff-old">null,
</del>
<ins class="diff-chg">a
</ins><a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition"><ins class="diff-chg">
subject
definition
</ins></a><ins class="diff-chg">
or
</ins>
an
<del class="diff-old">IRI
,
</del>
<ins class="diff-chg">array
of
zero
</ins>
or
<del class="diff-old">a
JSON
object
</del>
<ins class="diff-chg">more
</ins><a class="tref internalDFN" title="subject_definition" href="#dfn-subject_definition"><ins class="diff-chg">
subject
definitions
</ins>
</a>.
</li>
<li>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
a
<code>
@set
</code>
key
<em class="rfc2119" title="must not">
must
not
</em>
have
any
other
keys.
</li>
<li>
A
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
containing
a
<code>
@list
</code>
key
<em class="rfc2119" title="must not">
must
not
</em>
have
any
other
keys.
</li>
<li>
The
value
of
an
<code>
@set
</code>
or
<code>
@list
</code>
key
can
be
a
string,
a
number,
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
or
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
containing
a
combination
of
the
allowed
values.
</li>
<li>
For
each
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>
that
contains
a
<code>
@value
</code>
key:
<ol>
<li>
It
<em class="rfc2119" title="may">
may
</em>
have
a
<code>
@language
</code>
or
<code>
@type
</code>
property
and
<em class="rfc2119" title="must not">
must
not
</em>
have
any
other
properties.
</li>
<li>
It
<em class="rfc2119" title="must not">
must
not
</em>
contain
both
the
<code>
@language
</code>
and
<code>
@type
</code>
keys
at
the
same
time.
</li>
<li>
The
value
of
the
<code>
@value
</code>
key
<em class="rfc2119" title="must">
must
</em>
be
a
string
or
a
number.
</li>
<li>
The
value
of
the
<code>
@language
</code>
key
<em class="rfc2119" title="must">
must
</em>
be
<code>
null
</code>
or
a
string
in
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-BCP47">
BCP47
</a>
</cite>
]
format.
</li>
<li>
The
value
of
<code>
@type
</code>
<em class="rfc2119" title="must">
must
</em>
be
<code>
null
</code>,
a
<a class="tref internalDFN" title="term" href="#dfn-term">
term
</a>,
a
<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
compact
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
an
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>,
a
<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
JSON
object
</a>,
or
an
<a class="tref internalDFN" title="array" href="#dfn-array">
array
</a>
containing
a
combination
of
the
allowed
values.
</li>
</ol>
</li>
<li>
In
the
body
of
a
JSON-LD
document,
the
value
of
<code>
@type
</code>
<em class="rfc2119" title="must not">
must
not
</em>
be
<code>
@id
</code>.
This
is
in
contrast
to
the
use
of
<code>
@type
</code>
in
the
<code>
@context
</code>,
where
this
is
allowed.
</li>
</ol>
</div>
<div class="appendix informative section" id="relationship-to-other-rdf-formats">
<h2>
<span class="secno">
B.
</span>
<del class="diff-old">Markup
Examples
</del>
<ins class="diff-chg">Relationship
to
other
RDF
Formats
</ins>
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<div class="issue">
<div class="issue-title">
<span>
<ins class="diff-new">Issue
6
</ins></span></div><p class=""><ins class="diff-new">
The
intent
of
the
Working
Group
and
the
Editors
of
this
specification
is
to
eventually
align
terminology
used
in
this
document
with
the
terminology
used
in
the
RDF
Concepts
document
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS"><ins class="diff-new">
RDF-CONCEPTS
</ins></a></cite><ins class="diff-new">
]
to
the
extent
to
which
it
makes
sense
to
do
so.
In
general,
if
there
is
an
analogue
to
terminology
used
in
this
document
in
the
RDF
Concepts
document,
the
preference
is
to
use
the
terminology
in
the
RDF
Concepts
document.
</ins></p></div>
<p>
JSON-LD
is
a
specification
for
representing
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
in
JSON.
A
common
way
of
working
with
Linked
Data
is
through
<dfn title="rdf" id="dfn-rdf">
RDF
</dfn>,
the
Resource
Description
Framework.
RDF
can
be
expressed
using
JSON-LD
by
associating
JSON-LD
concepts
such
as
<code>
@id
</code>
and
<code>
@type
</code>
with
the
equivalent
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s
in
RDF.
Further
information
about
RDF
may
be
found
in
the
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-PRIMER">
RDF-PRIMER
</a>
</cite>
].
</p>
<p>
The
JSON-LD
markup
examples
below
demonstrate
how
JSON-LD
can
be
used
to
express
semantic
data
marked
up
in
other
languages
<ins class="diff-new">and
data
models
</ins>
such
as
<ins class="diff-new">RDF,
</ins>
Turtle,
RDFa,
Microformats,
and
Microdata.
These
sections
are
merely
provided
as
<del class="diff-old">proof
</del>
<ins class="diff-chg">evidence
</ins>
that
JSON-LD
is
very
flexible
in
what
it
can
express
across
different
<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
Linked
Data
</a>
approaches.
Further
information
on
transforming
JSON-LD
into
RDF
are
detailed
in
the
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
JSON-LD-API
</a>
</cite>
].
</p>
<div id="rdf" class="section">
<h3>
<span class="secno">
B.1
</span>
<ins class="diff-new">RDF
</ins></h3><p><em><ins class="diff-new">
This
section
is
non-normative.
</ins></em></p><p><ins class="diff-new">
The
RDF
data
model,
as
outlined
in
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS"><ins class="diff-new">
RDF-CONCEPTS
</ins></a></cite><ins class="diff-new">
],
is
an
abstract
syntax
for
representing
a
directed
graph
of
information.
JSON-LD
is
capable
of
serializing
any
RDF
graph,
and
performing
full
RDF
to
JSON-LD
to
RDF
round-tripping.
A
complete
description
of
how
JSON-LD
maps
to
RDF
and
algorithms
detailing
how
one
can
convert
from
RDF
to
JSON-LD
and
from
JSON-LD
to
RDF
are
included
in
the
JSON-LD
API
[
</ins><cite><a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API"><ins class="diff-new">
JSON-LD-API
</ins></a></cite><ins class="diff-new">
]
specification.
</ins></p></div><div id="turtle" class="section"><h3><span class="secno"><ins class="diff-new">
B.2
</ins></span>
Turtle
</h3>
<p>
The
following
are
examples
of
<del class="diff-old">representing
</del>
<ins class="diff-chg">converting
</ins>
<a class="tref internalDFN" title="rdf" href="#dfn-rdf">
RDF
</a>
<del class="diff-old">as
</del>
expressed
in
[
<cite>
<del class="diff-old">TURTLE
</del>
<a class="bibref" rel="biblioentry" href="#bib-TURTLE-TR">
<ins class="diff-chg">TURTLE-TR
</ins>
</a>
</cite>
]
into
JSON-LD.
</p>
<div id="prefix-definitions" class="section">
<h4>
<span class="secno">
<del class="diff-old">B.1.1
</del>
<ins class="diff-chg">B.2.1
</ins>
</span>
Prefix
definitions
</h4>
<p>
<em>
<ins class="diff-new">This
section
is
non-normative.
</ins></em></p>
<p>
The
JSON-LD
context
has
direct
equivalents
for
the
Turtle
<code>
@prefix
</code>
declaration:
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
</del>
<div class="example"><div class="example-title"><span>Example 53</span></div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
  foaf:name &quot;Manu Sporny&quot;;
foaf:homepage
&lt;http://manu.sporny.org/&gt;
.
</pre>
<del class="diff-old">{
</del>
</div>
<div class="example"><div class="example-title"><span>Example 54</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;: &quot;http://manu.sporny.org/i/public&quot;,
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;: { &quot;@id&quot;: &quot;http://manu.sporny.org/&quot; }
}
</pre>
</div>
<div class="note">
<div class="note-title">
<span>
<ins class="diff-new">Note
</ins></span></div><div class="">
<p>
JSON-LD
has
no
equivalent
for
the
Turtle
<code>
@base
</code>
declaration.
Instead,
authors
may
use
a
prefix
definition
to
resolve
<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
relative
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>
s:
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 55</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    <span class="diff">&quot;base&quot;: &quot;http://manu.sporny.org/&quot;,</span>
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;: <span class="diff">&quot;base:i/public&quot;</span>,
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
  &quot;foaf:homepage&quot;: { &quot;@id&quot;: <span class="diff">&quot;base&quot; </span>}
}
</pre>
</div>
</div>
</div>
</div>
<div id="embedding-1" class="section">
<h4>
<span class="secno">
<del class="diff-old">B.1.2
</del>
<ins class="diff-chg">B.2.2
</ins>
</span>
Embedding
</h4>
<p>
Both
Turtle
and
JSON-LD
allow
embedding
of
objects,
although
Turtle
only
allows
embedding
of
objects
which
use
<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
unlabeled
node
</a>
identifiers.
</p>
</div>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
</del>
<div class="example"><div class="example-title"><span>Example 56</span></div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://manu.sporny.org/i/public&gt;
  a foaf:Person;
  foaf:name &quot;Manu Sporny&quot;;
foaf:knows
[
a
foaf:Person;
foaf:name
&quot;Gregg
Kellogg&quot;
]
.
</pre>
<del class="diff-old">{
</del>
</div>
<div class="example"><div class="example-title"><span>Example 57</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;: &quot;http://manu.sporny.org/i/public&quot;,
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
  &quot;foaf:knows&quot;:
  {
    &quot;@type&quot;: &quot;foaf:Person&quot;,
    &quot;foaf:name&quot;: &quot;Gregg Kellogg&quot;
  }
}
</pre>
</div>
<div id="lists" class="section">
<h4>
<span class="secno">
<del class="diff-old">B.1.3
</del>
<ins class="diff-chg">B.2.3
</ins>
</span>
Lists
</h4>
<p>
Both
JSON-LD
and
Turtle
can
represent
sequential
lists
of
values.
</p>
<del class="diff-old">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
</del>
<div class="example"><div class="example-title"><span>Example 58</span></div><pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
&lt;http://example.org/people#joebob&gt; a foaf:Person;
  foaf:name &quot;Joe Bob&quot;;
foaf:nick
(
&quot;joe&quot;
&quot;bob&quot;
&quot;jaybee&quot;
)
.
</pre>
<del class="diff-old">{
</del>
</div>
<div class="example"><div class="example-title"><span>Example 59</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
  &quot;@type&quot;: &quot;foaf:Person&quot;,
  &quot;foaf:name&quot;: &quot;Joe Bob&quot;,
  &quot;foaf:nick&quot;:
  {
    &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]
  }
}
</pre>
</div>
</div>
</div>
<div id="rdfa" class="section">
<h3>
<span class="secno">
<del class="diff-old">B.2
</del>
<ins class="diff-chg">B.3
</ins>
</span>
RDFa
</h3>
<p>
The
following
example
describes
three
people
with
their
respective
names
and
homepages.
</p>
<del class="diff-old">&gt;
</del>
<div class="example"><div class="example-title"><span>Example 60</span></div><pre class="example">&lt;div <span class="diff">prefix=&quot;foaf: http://xmlns.com/foaf/0.1/&quot;</span>&gt;
   &lt;ul&gt;
      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/bob/&quot; property=&quot;foaf:name&quot; </span>&gt;Bob&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/eve/&quot; property=&quot;foaf:name&quot; </span>&gt;Eve&lt;/a&gt;
      &lt;/li&gt;
      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/manu/&quot; property=&quot;foaf:name&quot; </span>&gt;Manu&lt;/a&gt;
      &lt;/li&gt;
   &lt;/ul&gt;
&lt;/div&gt;
</pre>
</div>
<p>
An
example
JSON-LD
implementation
using
a
single
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
is
described
below.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 61</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;
  },
  &quot;@graph&quot;:
  [
    {
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/bob/&quot;,
      &quot;foaf:name&quot;: &quot;Bob&quot;
    },
    {
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/eve/&quot;,
      &quot;foaf:name&quot;: &quot;Eve&quot;
    },
    {
      &quot;@type&quot;: &quot;foaf:Person&quot;,
      &quot;foaf:homepage&quot;: &quot;http://example.com/manu/&quot;,
      &quot;foaf:name&quot;: &quot;Manu&quot;
    }
  ]
}
</pre>
</div>
</div>
<div id="microformats" class="section">
<h3>
<span class="secno">
<del class="diff-old">B.3
</del>
<ins class="diff-chg">B.4
</ins>
</span>
Microformats
</h3>
<p>
The
following
example
uses
a
simple
Microformats
hCard
example
to
express
how
the
Microformat
is
represented
in
JSON-LD.
</p>
<del class="diff-old">&lt;div class=&quot;vcard&quot;&gt;
</del>
<div class="example"><div class="example-title"><span>Example 62</span></div><pre class="example">&lt;div class=&quot;vcard&quot;&gt;
 &lt;a class=&quot;url fn&quot; href=&quot;http://tantek.com/&quot;&gt;Tantek Çelik&lt;/a&gt;
&lt;/div&gt;
</pre>
</div>
<p>
The
representation
of
the
hCard
expresses
the
Microformat
terms
in
the
<a class="tref internalDFN" title="context" href="#dfn-context">
context
</a>
and
uses
them
directly
for
the
<code>
url
</code>
and
<code>
fn
</code>
properties.
Also
note
that
the
Microformat
to
JSON-LD
processor
has
generated
the
proper
URL
type
for
<code>
http://tantek.com/
</code>.
</p>
<del class="diff-old">{
</del>
<div class="example"><div class="example-title"><span>Example 63</span></div><pre class="example">{
  &quot;@context&quot;:
  {
    &quot;vcard&quot;: &quot;http://microformats.org/profile/hcard#vcard&quot;,
    &quot;url&quot;:
    {
      &quot;@id&quot;: &quot;http://microformats.org/profile/hcard#url&quot;,
      &quot;@type&quot;: &quot;@id&quot;
    },
    &quot;fn&quot;: &quot;http://microformats.org/profile/hcard#fn&quot;
  },
  &quot;@type&quot;: &quot;vcard&quot;,
  &quot;url&quot;: &quot;http://tantek.com/&quot;,
  &quot;fn&quot;: &quot;Tantek Çelik&quot;
}
</pre>
</div>
</div>
<div id="microdata" class="section">
<h3>
<span class="secno">
<del class="diff-old">B.4
</del>
<ins class="diff-chg">B.5
</ins>
</span>
Microdata
</h3>
<p>
The
microdata
example
below
expresses
book
information
as
a
microdata
Work
item.
</p>
<del class="diff-old">&lt;dl itemscope
</del>
<div class="example"><div class="example-title"><span>Example 64</span></div><pre class="example">&lt;dl itemscope
    itemtype=&quot;http://purl.org/vocab/frbr/core#Work&quot;
    itemid=&quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;&gt;
 &lt;dt&gt;Title&lt;/dt&gt;
 &lt;dd&gt;&lt;cite itemprop=&quot;http://purl.org/dc/terms/title&quot;&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
 &lt;dt&gt;By&lt;/dt&gt;
 &lt;dd&gt;&lt;span itemprop=&quot;http://purl.org/dc/terms/creator&quot;&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
 &lt;dt&gt;Format&lt;/dt&gt;
 &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
     itemscope
     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
     itemid=&quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;&gt;
  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/BOOK&quot;&gt;
  Print
 &lt;/dd&gt;
 &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
     itemscope
     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
     itemid=&quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;&gt;
  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/EBOOK&quot;&gt;
  Ebook
 &lt;/dd&gt;
&lt;/dl&gt;
</pre>
</div>
<p>
Note
that
the
JSON-LD
representation
of
the
Microdata
information
stays
true
to
the
desires
of
the
Microdata
community
to
avoid
contexts
and
instead
refer
to
items
by
their
full
<a class="tref internalDFN" title="iri" href="#dfn-iri">
<abbr title="Internationalized Resource Identifier">
IRI
</abbr>
</a>.
</p>
<del class="diff-old">[
</del>
<div class="example"><div class="example-title"><span>Example 65</span></div><pre class="example">[
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Work&quot;,
    &quot;http://purl.org/dc/terms/title&quot;: &quot;Just a Geek&quot;,
    &quot;http://purl.org/dc/terms/creator&quot;: &quot;Whil Wheaton&quot;,
    &quot;http://purl.org/vocab/frbr/core#realization&quot;:
    [
      &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;,
      &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;
    ]
  },
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/BOOK&quot;
  },
  {
    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;,
    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/EBOOK&quot;
  }
]
</pre>
</div>
</div>
</div>
<div class="appendix informative section" id="iana-considerations">
<h2>
<span class="secno">
C.
</span>
IANA
Considerations
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
This
section
is
included
merely
for
standards
community
review
and
will
be
submitted
to
the
Internet
Engineering
Steering
Group
if
this
specification
becomes
a
W3C
Recommendation.
</p>
<h2 id="application-ld-json">
application/ld+json
</h2>
<dl>
<dt>
Type
name:
</dt>
<dd>
application
</dd>
<dt>
Subtype
name:
</dt>
<dd>
ld+json
</dd>
<dt>
Required
parameters:
</dt>
<dd>
None
</dd>
<dt>
Optional
parameters:
</dt>
<dd>
<dl>
<dt>
<code>
form
</code>
</dt>
<dd>
Determines
the
serialization
form
for
the
JSON-LD
document.
The
only
valid
value
at
the
moment
is
<code>
expanded
</code>.
If
no
form
is
specified
in
an
HTTP
request
header
to
an
HTTP
server,
the
server
<em class="rfc2119" title="may">
may
</em>
choose
any
form.
If
no
form
is
specified
in
an
HTTP
response,
the
form
<em class="rfc2119" title="must not">
must
not
</em>
be
assumed
to
take
any
particular
form.
</dd>
</dl>
</dd>
<dt>
Encoding
considerations:
</dt>
<dd>
The
same
as
the
<code>
application/json
</code>
MIME
media
type.
</dd>
<dt>
Security
considerations:
</dt>
<dd>
Since
JSON-LD
is
intended
to
be
a
pure
data
exchange
format
for
directed
graphs,
the
serialization
<em class="rfc2119" title="should not">
should
not
</em>
be
passed
through
a
code
execution
mechanism
such
as
JavaScript's
<code>
eval()
</code>
function.
It
is
<em class="rfc2119" title="recommended">
recommended
</em>
that
a
conforming
parser
does
not
attempt
to
directly
evaluate
the
JSON-LD
serialization
and
instead
purely
parse
the
input
into
a
language-native
data
structure.
</dd>
<dt>
Interoperability
considerations:
</dt>
<dd>
Not
Applicable
</dd>
<dt>
Published
specification:
</dt>
<dd>
The
<a href="http://json-ld.org/spec/latest/">
JSON-LD
</a>
specification.
</dd>
<dt>
Applications
that
use
this
media
type:
</dt>
<dd>
Any
programming
environment
that
requires
the
exchange
of
directed
graphs.
Implementations
of
JSON-LD
have
been
created
for
JavaScript,
Python,
Ruby,
PHP
and
C++.
</dd>
<dt>
Additional
information:
</dt>
<dd>
<dl>
<dt>
Magic
number(s):
</dt>
<dd>
Not
Applicable
</dd>
<dt>
File
extension(s):
</dt>
<dd>.jsonld
</dd>
<dt>
Macintosh
file
type
code(s):
</dt>
<dd>
TEXT
</dd>
</dl>
</dd>
<dt>
Person
&amp;
email
address
to
contact
for
further
information:
</dt>
<dd>
Manu
Sporny
&lt;msporny@digitalbazaar.com&gt;
</dd>
<dt>
Intended
usage:
</dt>
<dd>
Common
</dd>
<dt>
Restrictions
on
usage:
</dt>
<dd>
None
</dd>
<dt>
Author(s):
</dt>
<dd>
Manu
Sporny,
Gregg
Kellogg,
Markus
Lanthaler,
Dave
Longley
</dd>
<dt>
Change
controller:
</dt>
<dd>
W3C
</dd>
</dl>
<p>
Fragment
identifiers
used
with
<a href="#application-ld-json">
application/ld+json
</a>
resources
<em class="rfc2119" title="may">
may
</em>
identify
a
node
in
the
<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
linked
data
graph
</a>
expressed
in
the
resource.
This
idiom,
which
is
also
used
in
RDF
[
<cite>
<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
RDF-CONCEPTS
</a>
</cite>
],
gives
a
simple
way
to
&quot;mint&quot;
new,
document-local
IRIs
to
label
nodes
and
therefore
contributes
considerably
to
the
expressive
power
of
JSON-LD.
</p>
</div>
<div class="appendix informative section" id="acknowledgements">
<h2>
<span class="secno">
D.
</span>
Acknowledgements
</h2>
<p>
<em>
This
section
is
non-normative.
</em>
</p>
<p>
The
editors
would
like
to
thank
Mark
Birbeck,
who
provided
a
great
deal
of
the
initial
push
behind
the
JSON-LD
work
via
his
work
on
RDFj,
Dave
<del class="diff-old">Longley,
Dave
</del>
Lehn
and
Mike
Johnson
who
reviewed,
provided
feedback,
and
performed
several
implementations
of
the
specification,
and
Ian
Davis,
who
created
RDF/JSON.
Thanks
also
to
Nathan
Rixham,
Bradley
P.
Allen,
Kingsley
Idehen,
Glenn
McDonald,
Alexandre
Passant,
Danny
Ayers,
Ted
Thibodeau
Jr.,
Olivier
Grisel,
<del class="diff-old">Niklas
Lindström,
Markus
Lanthaler,
</del>
<ins class="diff-chg">Josh
Mandel,
Eric
Prud'hommeaux,
David
Wood,
Guus
Schreiber,
Pat
Hayes,
Sandro
Hawke,
</ins>
and
Richard
Cyganiak
for
their
input
on
the
specification.
</p>
</div>
<div id="references" class="appendix section">
<h2>
<span class="secno">
E.
</span>
References
</h2>
<div id="normative-references" class="section">
<h3>
<span class="secno">
E.1
</span>
Normative
references
</h3>
<dl class="bibliography">
<dt id="bib-BCP47">
[BCP47]
</dt>
<dd>
A.
<del class="diff-old">Phillips,
</del>
<ins class="diff-chg">Phillips;
</ins>
M.
Davis.
<a href="http://tools.ietf.org/html/bcp47">
<cite>
Tags
for
Identifying
Languages
</cite>
</a>
September
2009.
IETF
Best
Current
Practice.
URL:
<del class="diff-old">http://tools.ietf.org/rfc/bcp/bcp47.txt
</del>
<a href="http://tools.ietf.org/html/bcp47">
<ins class="diff-chg">http://tools.ietf.org/html/bcp47
</ins></a></dd><dt id="bib-JSON-LD-API"><ins class="diff-chg">
[JSON-LD-API]
</ins></dt><dd><cite><a href="http://json-ld.org/spec/ED/json-ld-api/20120524/"><ins class="diff-chg">
The
JSON-LD
API
1.0
</ins></a></cite><ins class="diff-chg">
Manu
Sporny,
Gregg
Kellogg,
Dave
Longley,
Markus
Lanthaler,
Editors.
World
Wide
Web
Consortium
(work
in
progress).
24
May
2012.
Editor's
Draft.
This
edition
of
the
JSON-LD
Syntax
specification
is
http://json-ld.org/spec/ED/json-ld-api/20120524/.
The
</ins><a href="http://json-ld.org/spec/latest/json-ld-api/"><ins class="diff-chg">
latest
edition
of
the
JSON-LD
Syntax
</ins></a><ins class="diff-chg">
is
available
at
http://json-ld.org/spec/latest/json-ld-api/
</ins></dd><dt id="bib-RDF-CONCEPTS"><ins class="diff-chg">
[RDF-CONCEPTS]
</ins></dt><dd><cite><a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/"><ins class="diff-chg">
RDF
1.1
Concepts
and
Abstract
Syntax
</ins></a></cite><ins class="diff-chg">
Richard
Cyganiak,
David
Wood,
Editors.
World
Wide
Web
Consortium
(work
in
progress).
30
May
2012.
Editor's
Draft.
This
edition
of
the
JSON-LD
Syntax
specification
is
http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/.
The
</ins><a href="http://www.w3.org/TR/rdf11-concepts/"><ins class="diff-chg">
latest
edition
of
the
JSON-LD
Syntax
</ins>
</a>
<ins class="diff-new">is
available
at
http://www.w3.org/TR/rdf11-concepts/
</ins>
</dd>
<dt id="bib-RFC3987">
[RFC3987]
</dt>
<dd>
M.
Dürst;
M.
Suignard.
<a href="http://www.ietf.org/rfc/rfc3987.txt">
<cite>
Internationalized
Resource
Identifiers
(IRIs).
</cite>
</a>
January
2005.
Internet
RFC
3987.
URL:
<a href="http://www.ietf.org/rfc/rfc3987.txt">
http://www.ietf.org/rfc/rfc3987.txt
</a>
</dd>
<dt id="bib-RFC4627">
[RFC4627]
</dt>
<dd>
D.
Crockford.
<a href="http://www.ietf.org/rfc/rfc4627.txt">
<cite>
The
application/json
Media
Type
for
JavaScript
Object
Notation
(JSON)
</cite>
</a>
July
2006.
Internet
RFC
4627.
URL:
<a href="http://www.ietf.org/rfc/rfc4627.txt">
http://www.ietf.org/rfc/rfc4627.txt
</a>
</dd>
<dt id="bib-RFC5988">
[RFC5988]
</dt>
<del class="diff-old">M.
Nottingham.
</del>
<dd>
<cite>
<a href="http://tools.ietf.org/rfc/rfc5988">
Web
Linking
</a>
</cite>
<ins class="diff-new">M.
Nottingham.
Editor.
</ins>
October
2010.
IETF
Standard.
URL:
<a href="http://tools.ietf.org/rfc/rfc5988.txt">
http://tools.ietf.org/rfc/rfc5988.txt
</a>
</dd>
</dl>
</div>
<div id="informative-references" class="section">
<h3>
<span class="secno">
E.2
</span>
Informative
references
</h3>
<del class="diff-old">[JSON-LD-API]
Manu
Sporny,
Gregg
Kellogg,
Dave
Longley,
Markus
Lanthaler,
Eds.
JSON-LD
API
Latest.
W3C
Editor's
Draft.
URL:
http://json-ld.org/spec/latest/json-ld-api/
[RDF-CONCEPTS]
Graham
Klyne;
Jeremy
J.
Carroll.
Resource
Description
Framework
(RDF):
Concepts
and
Abstract
Syntax.
10
February
2004.
W3C
Recommendation.
URL:
http://www.w3.org/TR/2004/REC-rdf-concepts-20040210
</del>
<dl class="bibliography">
<dt id="bib-RDF-PRIMER">
[RDF-PRIMER]
</dt>
<dd>
Frank
Manola;
Eric
Miller.
<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
<cite>
RDF
Primer.
</cite>
</a>
10
February
2004.
W3C
Recommendation.
URL:
<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
http://www.w3.org/TR/2004/REC-rdf-primer-20040210/
</a>
</dd>
<dt id="bib-RDFA-CORE">
[RDFA-CORE]
</dt>
<dd>
Shane
McCarron;
et
al.
<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120508/">
<cite>
RDFa
Core
1.1:
Syntax
and
processing
rules
for
embedding
RDF
through
attributes.
</cite>
</a>
<del class="diff-old">8
May
</del>
<ins class="diff-chg">7
June
</ins>
2012.
W3C
<del class="diff-old">Proposed
</del>
Recommendation.
URL:
<del class="diff-old">http://www.w3.org/TR/2012/PR-rdfa-core-20120508/
</del>
<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">
<ins class="diff-chg">http://www.w3.org/TR/2012/REC-rdfa-core-20120607/
</ins>
</a>
</dd>
<del class="diff-old">[TURTLE]
</del>
<dt id="bib-TURTLE-TR">
<ins class="diff-chg">[TURTLE-TR]
</ins>
</dt>
<del class="diff-old">David
Beckett,
Tim
Berners-Lee.
</del>
<dd>
<ins class="diff-chg">Eric
Prud'hommeaux,
Gavin
Carothers.
</ins>
<cite>
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
Turtle:
Terse
RDF
Triple
Language.
</a>
<del class="diff-old">January
2008.
</del>
</cite>
<ins class="diff-chg">09
August
2011.
</ins>
W3C
<del class="diff-old">Team
Submission.
</del>
<ins class="diff-chg">Working
Draft.
</ins>
URL:
<del class="diff-old">http://www.w3.org/TeamSubmission/turtle/
</del>
<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
<ins class="diff-chg">http://www.w3.org/TR/2011/WD-turtle-20110809/
</ins>
</a>
</dd>
</dl>
</div>
</div>
</body>
</html>
